orphaned-tool-call-sanitizer

orphaned-tool-call-sanitizer is a skill for Claude Code, Codex from ychampion/cskill-agents. It costs 27 tokens per session (394 once invoked), scanned A, original, MIT.

A history-cleaning step that removes assistant tool calls whose results were never recorded.

In plain words
What is it for?
It helps prepare reliable message history before passing it to another agent.
Why use it?
It prevents incomplete tool references from breaking a replayed conversation or confusing a subagent.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one. Also seen: mentions subagents.

Good fit It helps prepare reliable message history before passing it to another agent.

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Install with agentmods
npx agentmods add skills/ychampion/cskill-agents/orphaned-tool-call-sanitizer
Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent
npx skills add ychampion/cskill-agents --skill orphaned-tool-call-sanitizer
Clone the repo
git clone --depth 1 https://github.com/ychampion/cskill-agents

Made for: Claude Code, Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for orphaned-tool-call-sanitizer

README.md
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Your own site
<a href="https://agentmods.dev/skills/ychampion/cskill-agents/orphaned-tool-call-sanitizer"><img src="https://agentmods.dev/badge/skills/ychampion/cskill-agents/orphaned-tool-call-sanitizer/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for orphaned-tool-call-sanitizer

Your own site · 80×15
<a href="https://agentmods.dev/skills/ychampion/cskill-agents/orphaned-tool-call-sanitizer"><img src="https://agentmods.dev/badge/skills/ychampion/cskill-agents/orphaned-tool-call-sanitizer.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 27 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 394 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00027 $0.00394
Opus 5 $0.00014 $0.00197
Sonnet 5 $0.00005 $0.00079
Haiku 4.5 $0.00003 $0.00039

Measured 7d ago against content hash 7c0ed65abfd3, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-10, from the pricing page.

Security

Grade A, and why

orphaned-tool-call-sanitizer scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 7d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

agents/claude-code/skills/orphaned-tool-call-sanitizer/SKILL.md · 28 lines

What it actually says

SKILL: Orphaned Tool Call Sanitizer

Domain: messaging Trigger: When replaying history for a subagent, make sure assistant tool_use blocks never refer to tool_use_ids that lack results. Source Pattern: Distilled from reviewed subagent orchestration, isolation, and lifecycle implementations.

Core Method

Collect every tool_use_id emitted inside tool_result blocks on user messages, then drop any assistant message whose content includes a tool_use block that references an ID missing from that set. Non-assistant messages and assistant messages without tool_use blocks pass through unchanged, so only the incomplete invocations are pruned before query runs.

Key Rules

  • Build the tool use ids with results set exclusively from user-side tool_result blocks, since assistant messages can mention tool_use IDs that never resolved.
  • Treat every assistant message containing a tool_use entry whose id is absent from the result set as unsafe and remove it entirely.
  • Preserve progress, system, and clean assistant messages so the downstream agent still sees the rest of the context.
  • Run this sanitizer before providing initial messages to run agent so the async call path never sees an orphaned invocation.

Example Application

When the main agent forks to an Explore or Plan subagent, sanitize the shared history first so the subagent never inherits an assistant tool_use record that was never followed by a tool_result. The downstream query call then succeeds without rejecting the payload.

Anti-Patterns (What NOT to do)

  • Forwarding assistant messages with tool_use blocks that lack corresponding results; such payloads trigger API validation errors.
  • Waiting until after the query to drop the offending message, which already fails or leaves the transcript poisoned.
Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 7d ago First seen · 28 lines · 27 tokens per session scan A 7c0ed65abfd3

Subscribe to this mod's changes

orphaned-tool-call-sanitizer is a skill published in the GitHub repository ychampion/cskill-agents (36 stars, last pushed 5mo ago), licensed MIT. It adds 27 tokens to every session and 394 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-03.