{
  "id": "P297",
  "slug": "anthropic-thinking-disabled-claude-api",
  "status": "search-observed",
  "product": "Claude API",
  "family": "LLM model/API behavior drift",
  "canonical_url": "https://gitdocs.org/fix/anthropic-thinking-disabled-claude-api",
  "query_alias_url": "https://gitdocs.org/q/anthropic-thinking-disabled-claude-api",
  "markdown_url": "https://gitdocs.org/fix/anthropic-thinking-disabled-claude-api.md",
  "json_url": "https://gitdocs.org/api/fixes/anthropic-thinking-disabled-claude-api.json",
  "canonical_query": "Anthropic \"thinking\" \"disabled\" \"Claude\" API",
  "observed_codex_queries": [
    "site:docs.anthropic.com Claude API latency 400 SDK accepts field service_tier latency_sensitive",
    "site:docs.anthropic.com/en/docs Claude API thinking disabled 400 adaptive thinking model",
    "Anthropic \"thinking\" \"disabled\" \"Claude\" API",
    "Anthropic docs extended thinking API",
    "site:docs.anthropic.com \"adaptive thinking\" Claude API",
    "docs.anthropic.com claude api adaptive thinking effort levels",
    "https://docs.anthropic.com/en/api/messages",
    "https://platform.claude.com/docs/llms.txt",
    "site:anthropic.com/news \"adaptive thinking\" \"disabled\"",
    "\"Claude Opus 4.6: Adaptive thinking and 1M context window\"",
    "github anthropics anthropic-sdk-typescript thinking disabled adaptive thinking",
    "github.com anthropics anthropic-sdk-typescript \"type\": \"disabled\" \"thinking\"",
    "https://raw.githubusercontent.com/anthropics/anthropic-sdk-typescript/main/src/resources/messages/messages.ts",
    "'ThinkingConfig' in https://raw.githubusercontent.com/anthropics/anthropic-sdk-typescript/main/src/resources/messages/messages.ts",
    "https://platform.claude.com/docs/en/build-with-claude/adaptive-thinking"
  ],
  "organic_dependency_search_count": 15,
  "affected_versions": "",
  "exact_errors": [],
  "diagnosis": "SDK types may still accept fields that the selected hosted model rejects; model retirement, tokenizer, thinking, and tool behavior are external and fast-moving.",
  "before": "",
  "after": "",
  "verification": "Verifier checks current model ID, accepted payload, structured output/tool parsing, and behavior under retries.",
  "unsafe_fixes": [
    "Changing local code without checking the current external contract.",
    "Retrying the same install, build, or API call with no version/source change.",
    "Applying a broad unsafe bypass when a narrow compatibility fix is available."
  ],
  "last_verified_at": "2026-06-25",
  "neutral_validation": {
    "organic_search_observed": true,
    "organic_strict_pass": true,
    "no_web_counterfactual_run": false,
    "no_web_strict_pass": null,
    "search_necessity_under_fixture": null,
    "no_web_oracle_note": "Observed query evidence is separated from necessity proof; no-web and stale-contract counterfactuals should be tracked separately."
  },
  "source_trail": [
    {
      "url": "https://platform.claude.com/docs/en/about-claude/models/migration-guide",
      "label": "Claude model migration guide"
    },
    {
      "url": "https://docs.anthropic.com/en/api/messages",
      "label": "Official reference opened by Codex"
    },
    {
      "url": "https://platform.claude.com/docs/llms.txt",
      "label": "Official reference opened by Codex"
    },
    {
      "url": "https://raw.githubusercontent.com/anthropics/anthropic-sdk-typescript/main/src/resources/messages/messages.ts",
      "label": "Official reference opened by Codex"
    },
    {
      "url": "https://platform.claude.com/docs/en/build-with-claude/adaptive-thinking",
      "label": "Official reference opened by Codex"
    }
  ],
  "source_github_links": [
    {
      "url": "https://raw.githubusercontent.com/anthropics/anthropic-sdk-typescript/main/src/resources/messages/messages.ts",
      "label": "Official reference opened by Codex"
    }
  ]
}