Anthropic: stop_reason and stop_sequence not captured in span output #175

Closed
Bug
#185
Closed
Anthropic: stop_reason and stop_sequence not captured in span output#175
Bug
#185
Assignees
AbhiPrasad
Labels
bot-automationintegration: anthropic

Description

@braintrust-bot
braintrust-bot
bot
opened on Mar 29, 2026

Summary

The Anthropic integration's _log_message_to_span function extracts only role and content from the response message, dropping stop_reason and stop_sequence. Every other comparable wrapper in this repo captures the model's stop/finish reason in the span output.

Inconsistency across wrappers

WrapperCaptures stop/finish reason?Location
OpenAI (chat completions)Yes — finish_reason in output choicesoai.py ~line 354 (streaming), ~line 204 (non-streaming)
OpenAI (responses)Yes — status in response objectoai.py response wrapper
Google GenAIYes — finish_reason per candidategoogle_genai/tracing.py ~line 313
AgnoYes — finish_reason in aggregated outputagno/tracing.py ~line 293
AnthropicNoanthropic/tracing.py ~line 445

What is dropped

The Anthropic Message response object includes:

  • stop_reason: One of "end_turn", "max_tokens", "stop_sequence", "tool_use" — tells users why the model stopped generating
  • stop_sequence: The specific stop sequence matched (when stop_reason is "stop_sequence")
  • model: The resolved model name (e.g., claude-sonnet-4-5-20250929 when the request used claude-sonnet-4-5-latest)

The current code at _log_message_to_span (line ~445 of tracing.py) only extracts:

output= {
k: vfork, vin {"role": getattr(message, "role", None), "content": getattr(message, "content", None)}.items()
ifv
} orNone

Why this matters

  • stop_reason: "max_tokens" signals output truncation — a common debugging need
  • stop_reason: "tool_use" signals the model wants tool execution — critical for agent workflows
  • The resolved model name is needed for accurate cost tracking when using model aliases
  • Other wrappers in this repo already capture the equivalent field, so users may expect it from Anthropic too

Braintrust docs status

The Anthropic integration docs describe streaming and metric collection but do not mention stop_reason capture: not_found.

Upstream source

Anthropic Messages API reference documents stop_reason as a top-level field on every Message response.

Local files inspected

  • py/src/braintrust/integrations/anthropic/tracing.py — _log_message_to_span (line ~445) only extracts role and content
  • py/src/braintrust/integrations/anthropic/_utils.py — extract_anthropic_usage extracts token metrics but not response-level fields
  • py/src/braintrust/oai.py — OpenAI wrapper captures finish_reason for comparison
  • py/src/braintrust/integrations/google_genai/tracing.py — Google GenAI captures finish_reason for comparison

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Labels

bot-automationintegration: anthropic

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    , 'i'); if (__m === '*' || __re.test(location.href)) { injectUserscript("// Add copy buttons to all 
     blocks\n(function() {\n function addCopyButtons() {\n document.querySelectorAll('pre code').forEach(function(codeBlock) {\n if (codeBlock.parentElement.hasAttribute('data-copy-added')) return;\n codeBlock.parentElement.setAttribute('data-copy-added', 'true');\n \n var btn = document.createElement('button');\n btn.textContent = 'Copy';\n btn.style.cssText = 'position:absolute;top:4px;right:4px;padding:2px 8px;font-size:11px;background:#4ecdc4;border:none;border-radius:4px;color:#1a1a2e;cursor:pointer;opacity:0.7;transition:opacity 0.2s;';\n btn.onmouseover = function() { this.style.opacity = '1'; };\n btn.onmouseout = function() { this.style.opacity = '0.7'; };\n btn.onclick = function() {\n navigator.clipboard.writeText(codeBlock.textContent).then(function() {\n btn.textContent = 'Copied!';\n setTimeout(function() { btn.textContent = 'Copy'; }, 1500);\n });\n };\n codeBlock.parentElement.style.position = 'relative';\n codeBlock.parentElement.appendChild(btn);\n });\n }\n \n addCopyButtons();\n \n // Re-run on dynamic content\n var observer = new MutationObserver(addCopyButtons);\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Add Copy Buttons to Code Blocks");
}
} catch(__e) { console.warn('[Userscript:Add Copy Buttons to Code Blocks]', __e); }
})();
(function(){
try {
var __m = "github.com";
var __re = new RegExp('^' + "github\\.com" + '

    Skip to content
    Anthropic: stop_reason and stop_sequence not captured in span output #175
    Closed
    Bug
    #185
    Closed
    Anthropic: stop_reason and stop_sequence not captured in span output#175
    Bug
    #185
    Assignees
    AbhiPrasad
    Labels
    bot-automationintegration: anthropic
    Description
    @braintrust-bot
    braintrust-bot
    bot
    opened on Mar 29, 2026
    Summary
    The Anthropic integration's _log_message_to_span function extracts only role and content from the response message, dropping stop_reason and stop_sequence. Every other comparable wrapper in this repo captures the model's stop/finish reason in the span output.
    Inconsistency across wrappers
    WrapperCaptures stop/finish reason?Location
    OpenAI (chat completions)Yes — finish_reason in output choicesoai.py ~line 354 (streaming), ~line 204 (non-streaming)
    OpenAI (responses)Yes — status in response objectoai.py response wrapper
    Google GenAIYes — finish_reason per candidategoogle_genai/tracing.py ~line 313
    AgnoYes — finish_reason in aggregated outputagno/tracing.py ~line 293
    AnthropicNoanthropic/tracing.py ~line 445
    What is dropped
    The Anthropic Message response object includes:
    • stop_reason: One of "end_turn", "max_tokens", "stop_sequence", "tool_use" — tells users why the model stopped generating
    • stop_sequence: The specific stop sequence matched (when stop_reason is "stop_sequence")
    • model: The resolved model name (e.g., claude-sonnet-4-5-20250929 when the request used claude-sonnet-4-5-latest)
    The current code at _log_message_to_span (line ~445 of tracing.py) only extracts:
    output= {
k: vfork, vin {"role": getattr(message, "role", None), "content": getattr(message, "content", None)}.items()
ifv
} orNone
    Why this matters
    • stop_reason: "max_tokens" signals output truncation — a common debugging need
    • stop_reason: "tool_use" signals the model wants tool execution — critical for agent workflows
    • The resolved model name is needed for accurate cost tracking when using model aliases
    • Other wrappers in this repo already capture the equivalent field, so users may expect it from Anthropic too
    Braintrust docs status
    The Anthropic integration docs describe streaming and metric collection but do not mention stop_reason capture: not_found.
    Upstream source
    Anthropic Messages API reference documents stop_reason as a top-level field on every Message response.
    Local files inspected
    • py/src/braintrust/integrations/anthropic/tracing.py — _log_message_to_span (line ~445) only extracts role and content
    • py/src/braintrust/integrations/anthropic/_utils.py — extract_anthropic_usage extracts token metrics but not response-level fields
    • py/src/braintrust/oai.py — OpenAI wrapper captures finish_reason for comparison
    • py/src/braintrust/integrations/google_genai/tracing.py — Google GenAI captures finish_reason for comparison
    Metadata
    Metadata
    Assignees
    Labels
    bot-automationintegration: anthropic
    Type
    Bug
    Projects
    No projects
      Milestone
      No milestone
      Relationships
      None yet
      Development
      No branches or pull requests
      Issue actions
      
, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Force GitHub README to respect dark mode\n(function() {\n var style = document.createElement('style');\n style.textContent = '\n .markdown-body {\n color-scheme: dark light;\n }\n .markdown-body pre { background: #161b22 !important; }\n .markdown-body code { background: rgba(110, 118, 129, 0.4) !important; }\n .markdown-body table th, .markdown-body table td { border-color: #30363d !important; }\n .markdown-body img { background: #0d1117; }\n .markdown-body blockquote { border-left-color: #8b949e; }\n .markdown-body hr { border-color: #30363d; }\n ';\n document.head.appendChild(style);\n})();", "GitHub Dark Mode README Fix");
}
} catch(__e) { console.warn('[Userscript:GitHub Dark Mode README Fix]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

      Skip to content
      Anthropic: stop_reason and stop_sequence not captured in span output #175
      Closed
      Bug
      #185
      Closed
      Anthropic: stop_reason and stop_sequence not captured in span output#175
      Bug
      #185
      Assignees
      AbhiPrasad
      Labels
      bot-automationintegration: anthropic
      Description
      @braintrust-bot
      braintrust-bot
      bot
      opened on Mar 29, 2026
      Summary
      The Anthropic integration's _log_message_to_span function extracts only role and content from the response message, dropping stop_reason and stop_sequence. Every other comparable wrapper in this repo captures the model's stop/finish reason in the span output.
      Inconsistency across wrappers
      WrapperCaptures stop/finish reason?Location
      OpenAI (chat completions)Yes — finish_reason in output choicesoai.py ~line 354 (streaming), ~line 204 (non-streaming)
      OpenAI (responses)Yes — status in response objectoai.py response wrapper
      Google GenAIYes — finish_reason per candidategoogle_genai/tracing.py ~line 313
      AgnoYes — finish_reason in aggregated outputagno/tracing.py ~line 293
      AnthropicNoanthropic/tracing.py ~line 445
      What is dropped
      The Anthropic Message response object includes:
      • stop_reason: One of "end_turn", "max_tokens", "stop_sequence", "tool_use" — tells users why the model stopped generating
      • stop_sequence: The specific stop sequence matched (when stop_reason is "stop_sequence")
      • model: The resolved model name (e.g., claude-sonnet-4-5-20250929 when the request used claude-sonnet-4-5-latest)
      The current code at _log_message_to_span (line ~445 of tracing.py) only extracts:
      output= {
k: vfork, vin {"role": getattr(message, "role", None), "content": getattr(message, "content", None)}.items()
ifv
} orNone
      Why this matters
      • stop_reason: "max_tokens" signals output truncation — a common debugging need
      • stop_reason: "tool_use" signals the model wants tool execution — critical for agent workflows
      • The resolved model name is needed for accurate cost tracking when using model aliases
      • Other wrappers in this repo already capture the equivalent field, so users may expect it from Anthropic too
      Braintrust docs status
      The Anthropic integration docs describe streaming and metric collection but do not mention stop_reason capture: not_found.
      Upstream source
      Anthropic Messages API reference documents stop_reason as a top-level field on every Message response.
      Local files inspected
      • py/src/braintrust/integrations/anthropic/tracing.py — _log_message_to_span (line ~445) only extracts role and content
      • py/src/braintrust/integrations/anthropic/_utils.py — extract_anthropic_usage extracts token metrics but not response-level fields
      • py/src/braintrust/oai.py — OpenAI wrapper captures finish_reason for comparison
      • py/src/braintrust/integrations/google_genai/tracing.py — Google GenAI captures finish_reason for comparison
      Metadata
      Metadata
      Assignees
      Labels
      bot-automationintegration: anthropic
      Type
      Bug
      Projects
      No projects
        Milestone
        No milestone
        Relationships
        None yet
        Development
        No branches or pull requests
        Issue actions
        
, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Highlight search terms from Google/DuckDuckGo/Bing referrer\n(function() {\n var ref = document.referrer;\n var terms = [];\n \n if (ref.includes('google.com') || ref.includes('duckduckgo.com') || ref.includes('bing.com')) {\n var url = new URL(ref);\n var q = url.searchParams.get('q') || url.searchParams.get('p');\n if (q) {\n terms = q.split(/\\s+/).filter(function(t) { return t.length > 2; });\n }\n }\n \n if (terms.length === 0) return;\n \n var style = document.createElement('style');\n style.textContent = '.userscript-highlight { background: #fbbf24; color: #1a1a2e; padding: 1px 3px; border-radius: 2px; }';\n document.head.appendChild(style);\n \n function highlight(node) {\n if (node.nodeType === 3) { // text node\n var text = node.textContent;\n var found = false;\n terms.forEach(function(term) {\n var regex = new RegExp('(' + term.replace(/[.*+?^${}()|[\\]\\\\]/g, '\\\\') + ')', 'gi');\n if (regex.test(text)) {\n found = true;\n var frag = document.createDocumentFragment();\n var parts = text.split(regex);\n parts.forEach(function(part, i) {\n if (i % 2 === 0) {\n frag.appendChild(document.createTextNode(part));\n } else {\n var span = document.createElement('span');\n span.className = 'userscript-highlight';\n span.textContent = part;\n frag.appendChild(span);\n }\n });\n node.parentNode.replaceChild(frag, node);\n }\n });\n } else if (node.nodeType === 1 && node.childNodes) { // element\n var skipTags = ['SCRIPT', 'STYLE', 'NOSCRIPT', 'TEXTAREA', 'INPUT', 'SELECT'];\n if (!skipTags.includes(node.tagName)) {\n Array.from(node.childNodes).forEach(highlight);\n }\n }\n }\n \n highlight(document.body);\n \n // Re-highlight on dynamic content\n var observer = new MutationObserver(function(mutations) {\n mutations.forEach(function(m) {\n m.addedNodes.forEach(function(node) {\n if (node.nodeType === 1 || node.nodeType === 3) highlight(node);\n });\n });\n });\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Highlight Search Terms");
}
} catch(__e) { console.warn('[Userscript:Highlight Search Terms]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

        Skip to content
        Anthropic: stop_reason and stop_sequence not captured in span output #175
        Closed
        Bug
        #185
        Closed
        Anthropic: stop_reason and stop_sequence not captured in span output#175
        Bug
        #185
        Assignees
        AbhiPrasad
        Labels
        bot-automationintegration: anthropic
        Description
        @braintrust-bot
        braintrust-bot
        bot
        opened on Mar 29, 2026
        Summary
        The Anthropic integration's _log_message_to_span function extracts only role and content from the response message, dropping stop_reason and stop_sequence. Every other comparable wrapper in this repo captures the model's stop/finish reason in the span output.
        Inconsistency across wrappers
        WrapperCaptures stop/finish reason?Location
        OpenAI (chat completions)Yes — finish_reason in output choicesoai.py ~line 354 (streaming), ~line 204 (non-streaming)
        OpenAI (responses)Yes — status in response objectoai.py response wrapper
        Google GenAIYes — finish_reason per candidategoogle_genai/tracing.py ~line 313
        AgnoYes — finish_reason in aggregated outputagno/tracing.py ~line 293
        AnthropicNoanthropic/tracing.py ~line 445
        What is dropped
        The Anthropic Message response object includes:
        • stop_reason: One of "end_turn", "max_tokens", "stop_sequence", "tool_use" — tells users why the model stopped generating
        • stop_sequence: The specific stop sequence matched (when stop_reason is "stop_sequence")
        • model: The resolved model name (e.g., claude-sonnet-4-5-20250929 when the request used claude-sonnet-4-5-latest)
        The current code at _log_message_to_span (line ~445 of tracing.py) only extracts:
        output= {
k: vfork, vin {"role": getattr(message, "role", None), "content": getattr(message, "content", None)}.items()
ifv
} orNone
        Why this matters
        • stop_reason: "max_tokens" signals output truncation — a common debugging need
        • stop_reason: "tool_use" signals the model wants tool execution — critical for agent workflows
        • The resolved model name is needed for accurate cost tracking when using model aliases
        • Other wrappers in this repo already capture the equivalent field, so users may expect it from Anthropic too
        Braintrust docs status
        The Anthropic integration docs describe streaming and metric collection but do not mention stop_reason capture: not_found.
        Upstream source
        Anthropic Messages API reference documents stop_reason as a top-level field on every Message response.
        Local files inspected
        • py/src/braintrust/integrations/anthropic/tracing.py — _log_message_to_span (line ~445) only extracts role and content
        • py/src/braintrust/integrations/anthropic/_utils.py — extract_anthropic_usage extracts token metrics but not response-level fields
        • py/src/braintrust/oai.py — OpenAI wrapper captures finish_reason for comparison
        • py/src/braintrust/integrations/google_genai/tracing.py — Google GenAI captures finish_reason for comparison
        Metadata
        Metadata
        Assignees
        Labels
        bot-automationintegration: anthropic
        Type
        Bug
        Projects
        No projects
          Milestone
          No milestone
          Relationships
          None yet
          Development
          No branches or pull requests
          Issue actions
          
, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Strip utm_, fbclid, gclid, etc. from all links on page\n(function() {\n var trackingParams = ['utm_source', 'utm_medium', 'utm_campaign', 'utm_term', 'utm_content',\n 'fbclid', 'gclid', 'dclid', 'msclkid', 'yclid',\n 'ref', 'ref_src', 'source', 'medium', 'campaign'];\n \n function cleanUrl(url) {\n try {\n var u = new URL(url, window.location.origin);\n var changed = false;\n trackingParams.forEach(function(p) {\n if (u.searchParams.has(p)) {\n u.searchParams.delete(p);\n changed = true;\n }\n });\n return changed ? u.toString() : url;\n } catch (e) {\n return url;\n }\n }\n \n function cleanLinks() {\n document.querySelectorAll('a[href]').forEach(function(a) {\n var clean = cleanUrl(a.href);\n if (clean !== a.href) a.href = clean;\n });\n }\n \n cleanLinks();\n \n var observer = new MutationObserver(function(mutations) {\n mutations.forEach(function(m) {\n m.addedNodes.forEach(function(node) {\n if (node.nodeType === 1) {\n if (node.tagName === 'A') cleanLinks();\n node.querySelectorAll('a[href]').forEach(function(a) {\n var clean = cleanUrl(a.href);\n if (clean !== a.href) a.href = clean;\n });\n }\n });\n });\n });\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Remove Tracking Parameters from Links");
}
} catch(__e) { console.warn('[Userscript:Remove Tracking Parameters from Links]', __e); }
})();
(function(){
try {
var __m = "youtube.com";
var __re = new RegExp('^' + "youtube\\.com" + '

          Skip to content
          Anthropic: stop_reason and stop_sequence not captured in span output #175
          Closed
          Bug
          #185
          Closed
          Anthropic: stop_reason and stop_sequence not captured in span output#175
          Bug
          #185
          Assignees
          AbhiPrasad
          Labels
          bot-automationintegration: anthropic
          Description
          @braintrust-bot
          braintrust-bot
          bot
          opened on Mar 29, 2026
          Summary
          The Anthropic integration's _log_message_to_span function extracts only role and content from the response message, dropping stop_reason and stop_sequence. Every other comparable wrapper in this repo captures the model's stop/finish reason in the span output.
          Inconsistency across wrappers
          WrapperCaptures stop/finish reason?Location
          OpenAI (chat completions)Yes — finish_reason in output choicesoai.py ~line 354 (streaming), ~line 204 (non-streaming)
          OpenAI (responses)Yes — status in response objectoai.py response wrapper
          Google GenAIYes — finish_reason per candidategoogle_genai/tracing.py ~line 313
          AgnoYes — finish_reason in aggregated outputagno/tracing.py ~line 293
          AnthropicNoanthropic/tracing.py ~line 445
          What is dropped
          The Anthropic Message response object includes:
          • stop_reason: One of "end_turn", "max_tokens", "stop_sequence", "tool_use" — tells users why the model stopped generating
          • stop_sequence: The specific stop sequence matched (when stop_reason is "stop_sequence")
          • model: The resolved model name (e.g., claude-sonnet-4-5-20250929 when the request used claude-sonnet-4-5-latest)
          The current code at _log_message_to_span (line ~445 of tracing.py) only extracts:
          output= {
k: vfork, vin {"role": getattr(message, "role", None), "content": getattr(message, "content", None)}.items()
ifv
} orNone
          Why this matters
          • stop_reason: "max_tokens" signals output truncation — a common debugging need
          • stop_reason: "tool_use" signals the model wants tool execution — critical for agent workflows
          • The resolved model name is needed for accurate cost tracking when using model aliases
          • Other wrappers in this repo already capture the equivalent field, so users may expect it from Anthropic too
          Braintrust docs status
          The Anthropic integration docs describe streaming and metric collection but do not mention stop_reason capture: not_found.
          Upstream source
          Anthropic Messages API reference documents stop_reason as a top-level field on every Message response.
          Local files inspected
          • py/src/braintrust/integrations/anthropic/tracing.py — _log_message_to_span (line ~445) only extracts role and content
          • py/src/braintrust/integrations/anthropic/_utils.py — extract_anthropic_usage extracts token metrics but not response-level fields
          • py/src/braintrust/oai.py — OpenAI wrapper captures finish_reason for comparison
          • py/src/braintrust/integrations/google_genai/tracing.py — Google GenAI captures finish_reason for comparison
          Metadata
          Metadata
          Assignees
          Labels
          bot-automationintegration: anthropic
          Type
          Bug
          Projects
          No projects
            Milestone
            No milestone
            Relationships
            None yet
            Development
            No branches or pull requests
            Issue actions
            
, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Auto-enable theater mode on YouTube\n(function() {\n function tryTheater() {\n var btn = document.querySelector('button[aria-label=\"Theater mode\"], ytd-player #player button[title=\"Theater mode\"]');\n if (btn && !btn.classList.contains('activated')) {\n btn.click();\n }\n }\n \n // Try immediately\n tryTheater();\n \n // Try after navigation (SPA)\n var lastUrl = location.href;\n setInterval(function() {\n if (location.href !== lastUrl) {\n lastUrl = location.href;\n setTimeout(tryTheater, 500);\n }\n }, 1000);\n \n // Also try on player load\n var observer = new MutationObserver(tryTheater);\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "YouTube Theater Mode Default");
}
} catch(__e) { console.warn('[Userscript:YouTube Theater Mode Default]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

            Skip to content
            Anthropic: stop_reason and stop_sequence not captured in span output #175
            Closed
            Bug
            #185
            Closed
            Anthropic: stop_reason and stop_sequence not captured in span output#175
            Bug
            #185
            Assignees
            AbhiPrasad
            Labels
            bot-automationintegration: anthropic
            Description
            @braintrust-bot
            braintrust-bot
            bot
            opened on Mar 29, 2026
            Summary
            The Anthropic integration's _log_message_to_span function extracts only role and content from the response message, dropping stop_reason and stop_sequence. Every other comparable wrapper in this repo captures the model's stop/finish reason in the span output.
            Inconsistency across wrappers
            WrapperCaptures stop/finish reason?Location
            OpenAI (chat completions)Yes — finish_reason in output choicesoai.py ~line 354 (streaming), ~line 204 (non-streaming)
            OpenAI (responses)Yes — status in response objectoai.py response wrapper
            Google GenAIYes — finish_reason per candidategoogle_genai/tracing.py ~line 313
            AgnoYes — finish_reason in aggregated outputagno/tracing.py ~line 293
            AnthropicNoanthropic/tracing.py ~line 445
            What is dropped
            The Anthropic Message response object includes:
            • stop_reason: One of "end_turn", "max_tokens", "stop_sequence", "tool_use" — tells users why the model stopped generating
            • stop_sequence: The specific stop sequence matched (when stop_reason is "stop_sequence")
            • model: The resolved model name (e.g., claude-sonnet-4-5-20250929 when the request used claude-sonnet-4-5-latest)
            The current code at _log_message_to_span (line ~445 of tracing.py) only extracts:
            output= {
k: vfork, vin {"role": getattr(message, "role", None), "content": getattr(message, "content", None)}.items()
ifv
} orNone
            Why this matters
            • stop_reason: "max_tokens" signals output truncation — a common debugging need
            • stop_reason: "tool_use" signals the model wants tool execution — critical for agent workflows
            • The resolved model name is needed for accurate cost tracking when using model aliases
            • Other wrappers in this repo already capture the equivalent field, so users may expect it from Anthropic too
            Braintrust docs status
            The Anthropic integration docs describe streaming and metric collection but do not mention stop_reason capture: not_found.
            Upstream source
            Anthropic Messages API reference documents stop_reason as a top-level field on every Message response.
            Local files inspected
            • py/src/braintrust/integrations/anthropic/tracing.py — _log_message_to_span (line ~445) only extracts role and content
            • py/src/braintrust/integrations/anthropic/_utils.py — extract_anthropic_usage extracts token metrics but not response-level fields
            • py/src/braintrust/oai.py — OpenAI wrapper captures finish_reason for comparison
            • py/src/braintrust/integrations/google_genai/tracing.py — Google GenAI captures finish_reason for comparison
            Metadata
            Metadata
            Assignees
            Labels
            bot-automationintegration: anthropic
            Type
            Bug
            Projects
            No projects
              Milestone
              No milestone
              Relationships
              None yet
              Development
              No branches or pull requests
              Issue actions
              
, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Remove or un-stick sticky/fixed headers that block content\n(function() {\n function unstick() {\n document.querySelectorAll('header, nav, [role=\"banner\"], .header, .navbar, .sticky, .fixed-top, [style*=\"position: fixed\"], [style*=\"position:sticky\"]').forEach(function(el) {\n if (el.style.position === 'fixed' || el.style.position === 'sticky' || \n getComputedStyle(el).position === 'fixed' || getComputedStyle(el).position === 'sticky') {\n el.style.position = 'static';\n el.style.top = 'auto';\n el.style.zIndex = 'auto';\n }\n });\n }\n \n unstick();\n \n var observer = new MutationObserver(unstick);\n observer.observe(document.body, { childList: true, subtree: true, attributes: true, attributeFilter: ['style', 'class'] });\n})();", "Kill Sticky Headers");
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} catch(__e) { console.warn('[Userscript:Kill Sticky Headers]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

              Skip to content
              Anthropic: stop_reason and stop_sequence not captured in span output #175
              Closed
              Bug
              #185
              Closed
              Anthropic: stop_reason and stop_sequence not captured in span output#175
              Bug
              #185
              Assignees
              AbhiPrasad
              Labels
              bot-automationintegration: anthropic
              Description
              @braintrust-bot
              braintrust-bot
              bot
              opened on Mar 29, 2026
              Summary
              The Anthropic integration's _log_message_to_span function extracts only role and content from the response message, dropping stop_reason and stop_sequence. Every other comparable wrapper in this repo captures the model's stop/finish reason in the span output.
              Inconsistency across wrappers
              WrapperCaptures stop/finish reason?Location
              OpenAI (chat completions)Yes — finish_reason in output choicesoai.py ~line 354 (streaming), ~line 204 (non-streaming)
              OpenAI (responses)Yes — status in response objectoai.py response wrapper
              Google GenAIYes — finish_reason per candidategoogle_genai/tracing.py ~line 313
              AgnoYes — finish_reason in aggregated outputagno/tracing.py ~line 293
              AnthropicNoanthropic/tracing.py ~line 445
              What is dropped
              The Anthropic Message response object includes:
              • stop_reason: One of "end_turn", "max_tokens", "stop_sequence", "tool_use" — tells users why the model stopped generating
              • stop_sequence: The specific stop sequence matched (when stop_reason is "stop_sequence")
              • model: The resolved model name (e.g., claude-sonnet-4-5-20250929 when the request used claude-sonnet-4-5-latest)
              The current code at _log_message_to_span (line ~445 of tracing.py) only extracts:
              output= {
k: vfork, vin {"role": getattr(message, "role", None), "content": getattr(message, "content", None)}.items()
ifv
} orNone
              Why this matters
              • stop_reason: "max_tokens" signals output truncation — a common debugging need
              • stop_reason: "tool_use" signals the model wants tool execution — critical for agent workflows
              • The resolved model name is needed for accurate cost tracking when using model aliases
              • Other wrappers in this repo already capture the equivalent field, so users may expect it from Anthropic too
              Braintrust docs status
              The Anthropic integration docs describe streaming and metric collection but do not mention stop_reason capture: not_found.
              Upstream source
              Anthropic Messages API reference documents stop_reason as a top-level field on every Message response.
              Local files inspected
              • py/src/braintrust/integrations/anthropic/tracing.py — _log_message_to_span (line ~445) only extracts role and content
              • py/src/braintrust/integrations/anthropic/_utils.py — extract_anthropic_usage extracts token metrics but not response-level fields
              • py/src/braintrust/oai.py — OpenAI wrapper captures finish_reason for comparison
              • py/src/braintrust/integrations/google_genai/tracing.py — Google GenAI captures finish_reason for comparison
              Metadata
              Metadata
              Assignees
              Labels
              bot-automationintegration: anthropic
              Type
              Bug
              Projects
              No projects
                Milestone
                No milestone
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                None yet
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                No branches or pull requests
                Issue actions
                
, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Universal Dark Mode - works on any site\n(function() {\n var enabled = true;\n \n function applyDarkMode() {\n if (!enabled) return;\n \n // Create style element if it doesn't exist\n var style = document.getElementById('universal-dark-mode-style');\n if (!style) {\n style = document.createElement('style');\n style.id = 'universal-dark-mode-style';\n document.head.appendChild(style);\n }\n \n // Dark mode CSS - inverts colors but preserves images/video\n style.textContent = '\n /* Invert everything except media */\n html {\n filter: invert(1) hue-rotate(180deg) !important;\n background: #1a1a2e !important;\n }\n \n /* Restore images, videos, iframes, canvas */\n img, video, iframe, canvas, svg, picture, [style*=\"background-image\"] {\n filter: invert(1) hue-rotate(180deg) !important;\n }\n \n /* Preserve specific elements that should not be inverted */\n .no-dark-mode, .no-dark-mode *,\n [data-theme=\"light\"], [data-theme=\"light\"],\n .ace_editor, .ace_editor *,\n .CodeMirror, .CodeMirror *,\n .monaco-editor, .monaco-editor *,\n .markdown-body pre, .markdown-body pre *,\n .highlight, .highlight *,\n pre code, pre code * {\n filter: none !important;\n }\n \n /* Fix common UI elements */\n .modal, .popup, .dropdown-menu, .tooltip, .popover {\n filter: invert(1) hue-rotate(180deg) !important;\n background: #2d2d44 !important;\n border-color: #444 !important;\n }\n \n /* Scrollbars */\n ::-webkit-scrollbar { background: #1a1a2e !important; }\n ::-webkit-scrollbar-thumb { background: #444 !important; }\n ::-webkit-scrollbar-thumb:hover { background: #555 !important; }\n \n /* Selection */\n ::selection { background: #4ecdc4 !important; color: #1a1a2e !important; }\n ::-moz-selection { background: #4ecdc4 !important; color: #1a1a2e !important; }\n ';\n }\n \n function removeDarkMode() {\n var style = document.getElementById('universal-dark-mode-style');\n if (style) style.remove();\n }\n \n // Toggle with Alt+Shift+D\n document.addEventListener('keydown', function(e) {\n if (e.altKey && e.shiftKey && e.key === 'D') {\n e.preventDefault();\n enabled = !enabled;\n if (enabled) {\n applyDarkMode();\n console.log('[Universal Dark Mode] Enabled');\n } else {\n removeDarkMode();\n console.log('[Universal Dark Mode] Disabled');\n }\n }\n });\n \n // Apply on load\n applyDarkMode();\n \n // Re-apply on dynamic content\n var observer = new MutationObserver(function(mutations) {\n if (enabled && !document.getElementById('universal-dark-mode-style')) {\n applyDarkMode();\n }\n });\n observer.observe(document.head, { childList: true });\n \n console.log('[Universal Dark Mode] Loaded - Press Alt+Shift+D to toggle');\n})();", "Universal Dark Mode");
}
} catch(__e) { console.warn('[Userscript:Universal Dark Mode]', __e); }
})();
})();

                Skip to content
                Anthropic: stop_reason and stop_sequence not captured in span output #175
                Closed
                Bug
                #185
                Closed
                Anthropic: stop_reason and stop_sequence not captured in span output#175
                Bug
                #185
                Assignees
                AbhiPrasad
                Labels
                bot-automationintegration: anthropic
                Description
                @braintrust-bot
                braintrust-bot
                bot
                opened on Mar 29, 2026
                Summary
                The Anthropic integration's _log_message_to_span function extracts only role and content from the response message, dropping stop_reason and stop_sequence. Every other comparable wrapper in this repo captures the model's stop/finish reason in the span output.
                Inconsistency across wrappers
                WrapperCaptures stop/finish reason?Location
                OpenAI (chat completions)Yes — finish_reason in output choicesoai.py ~line 354 (streaming), ~line 204 (non-streaming)
                OpenAI (responses)Yes — status in response objectoai.py response wrapper
                Google GenAIYes — finish_reason per candidategoogle_genai/tracing.py ~line 313
                AgnoYes — finish_reason in aggregated outputagno/tracing.py ~line 293
                AnthropicNoanthropic/tracing.py ~line 445
                What is dropped
                The Anthropic Message response object includes:
                • stop_reason: One of "end_turn", "max_tokens", "stop_sequence", "tool_use" — tells users why the model stopped generating
                • stop_sequence: The specific stop sequence matched (when stop_reason is "stop_sequence")
                • model: The resolved model name (e.g., claude-sonnet-4-5-20250929 when the request used claude-sonnet-4-5-latest)
                The current code at _log_message_to_span (line ~445 of tracing.py) only extracts:
                output= {
k: vfork, vin {"role": getattr(message, "role", None), "content": getattr(message, "content", None)}.items()
ifv
} orNone
                Why this matters
                • stop_reason: "max_tokens" signals output truncation — a common debugging need
                • stop_reason: "tool_use" signals the model wants tool execution — critical for agent workflows
                • The resolved model name is needed for accurate cost tracking when using model aliases
                • Other wrappers in this repo already capture the equivalent field, so users may expect it from Anthropic too
                Braintrust docs status
                The Anthropic integration docs describe streaming and metric collection but do not mention stop_reason capture: not_found.
                Upstream source
                Anthropic Messages API reference documents stop_reason as a top-level field on every Message response.
                Local files inspected
                • py/src/braintrust/integrations/anthropic/tracing.py — _log_message_to_span (line ~445) only extracts role and content
                • py/src/braintrust/integrations/anthropic/_utils.py — extract_anthropic_usage extracts token metrics but not response-level fields
                • py/src/braintrust/oai.py — OpenAI wrapper captures finish_reason for comparison
                • py/src/braintrust/integrations/google_genai/tracing.py — Google GenAI captures finish_reason for comparison
                Metadata
                Metadata
                Assignees
                Labels
                bot-automationintegration: anthropic
                Type
                Bug
                Projects
                No projects
                  Milestone
                  No milestone
                  Relationships
                  None yet
                  Development
                  No branches or pull requests
                  Issue actions