fix(dedup): strip timestamps from array-form content blocks

[ygd58]

What

stripTimestamps in src/dedup.ts and normalizeForCache in src/response-cache.ts
only strip OpenClaw's injected timestamp prefix when a message's content is a plain
string. Anthropic-style content blocks (content: [{type: "text", text}, {type: "image_url", ...}]),
used for vision/multimodal messages, were never handled — the timestamp lives in the
leading text block's text field, not in content itself, so neither function's
string-only branch ever fires for these.

Impact

OpenClaw injects a fresh [DAY YYYY-MM-DD HH:MM TZ] timestamp on every request. For a
retried multimodal message (timeout, network blip, etc.):

• Dedup (dedup.ts): the retry hashes differently from the original, so it's never
  recognized as a duplicate — the same request can be paid for twice via x402.
• Response cache (response-cache.ts): the cache key never matches on retry, so it
  always misses and re-hits the upstream LLM unnecessarily.

Reproduced in isolation before fixing — same-content requests differing only by
timestamp hashed identically for plain-string content, but differently for array-form
content.

Fix

Both functions now also walk array-form content, stripping the timestamp prefix from
any {type: "text", text} block, mirroring the existing plain-string behavior.

Testing

• Added src/dedup.test.ts (new file) — 3 tests covering string content (existing
  behavior, unchanged), array content (the fix), and confirming array content that
  actually differs still produces different keys.
• Added 1 test to src/response-cache.test.ts covering the same array-content case.
• Full suite passes: npx vitest run → all tests green, no regressions.
• tsc --noEmit, eslint, and prettier --check all clean on the changed files.

Summary by CodeRabbit

• Bug Fixes

  • Improved request deduplication for multimodal messages with array-based content.
  • Improved response caching by recognizing equivalent requests with timestamped leading text blocks.
  • Preserved meaningful timestamps in later content blocks to avoid incorrect request matching.
  • Reduced unnecessary duplicate requests and repeated cache misses for multimodal content.

• Tests

  • Added coverage for timestamp normalization in deduplication and response-cache scenarios.

[coderabbitai]

Caution

Review failed

The pull request is closed.

ℹ️ Recent review info

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Configuration used: Path: .coderabbit.yaml

Review profile: CHILL

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Run ID: 9a6b3d7f-773a-4cb0-ac92-e02494404d09

📥 Commits

Reviewing files that changed from the base of the PR and between d968f4e and ab325ba.

📒 Files selected for processing (5)

• src/dedup.test.ts
• src/dedup.ts
• src/response-cache.test.ts
• src/response-cache.ts
• src/timestamp-strip.ts

---

📝 Walkthrough

Walkthrough

The change adds shared timestamp normalization for Anthropic-style array content. Request deduplication and response-cache key generation now strip injected timestamps only from the first text block. Tests cover stable keys and preservation of later or genuinely different content.

Changes

Timestamp normalization

Layer / File(s)	Summary
Shared timestamp normalization src/timestamp-strip.ts	Defines the shared timestamp pattern and strips it from only the first eligible text block.
Request hash normalization src/dedup.ts, src/dedup.test.ts	Request hashing uses the shared helper for array content. Tests cover stable hashes, later-block timestamp data, and genuinely different content.
Response cache key normalization src/response-cache.ts, src/response-cache.test.ts	Cache key generation uses the shared helper for array content. Tests cover stable keys, later-block timestamp data, and different content.

Estimated code review effort: 3 (Moderate) | ~20 minutes

Merge Risk: 🔵 Low · up to d968f

The change fixes timestamp handling for multimodal messages, but nested tool-result content can still remain timestamp-sensitive in cache keys, allowing some retries after the deduplication window to miss the cache and repeat an upstream request. The PR is mergeable with explicit owner awareness or a follow-up to align nested-content normalization and add regression coverage.

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 2 functions across 4 files.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly and concisely describes the main change: stripping timestamps from array-form content blocks for deduplication.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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🧪 Generate unit tests (beta)

• Create PR with unit tests

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[coderabbitai]

Actionable comments posted: 1

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Inline comments:
In `@src/response-cache.ts`:
- Line 107: Update the supported Anthropic tool_result normalization in the
response-cache path so nested content is recursively normalized by reusing the
existing dedup normalizer or matching its timestamp-stripping behavior, rather
than returning the unchanged block. Add a regression test covering nested
tool_result content across deduplication and response-cache lookups.

🪄 Autofix

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• Create a new PR with the fixes

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: CHILL

Plan: Pro Plus

Run ID: 69cd3a90-4452-4ec5-9f27-7de0797d4448

📥 Commits

Reviewing files that changed from the base of the PR and between 477413a and d968f4e.

📒 Files selected for processing (4)

• src/dedup.test.ts
• src/dedup.ts
• src/response-cache.test.ts
• src/response-cache.ts

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[VickyXAI]

Thanks @ygd58 — this is a real bug, and the PR nailed the diagnosis: the string-only branch never fires for array-form content, so multimodal retries could be paid twice. Verified locally: full suite green, and the strip functions feed key computation only (the proxy forwards the original body untouched).

Review (including two independent adversarial passes) converged on one scope issue, so I pushed a follow-up commit to your branch (ab325ba) rather than round-tripping:

Stripping was applied to every text block, but OpenClaw only injects into the first one. A bracketed timestamp starting a later text block is user data (e.g. a pasted log line like [Wed 2026-08-27 09:15 UTC] connection refused). Stripping it let two genuinely different requests collide on one key — the wrong cached response served for up to 10 min, or a distinct paid request wrongly deduped. Note the plain-string path never had this problem: the injected stamp is always the leading one there, so a user's own timestamp survives the single anchored replace.

The commit scopes the strip to the first type:"text" block, extracts the shared stripLeadingTextBlockTimestamp helper + TIMESTAMP_PATTERN into src/timestamp-strip.ts (so dedup and cache normalization can't drift — also addresses the CodeRabbit note), and adds regression tests for the non-leading-block and differing-content cases in both suites. One deliberate residual: stripTimestamps still recurses deeper than normalizeForCache (pre-existing design difference), but both now share the block-level logic.

Your tests and behavior for the intended case are unchanged and passing. Will credit you in the CHANGELOG on the next release.