aet-investigate

aet-investigate is a skill for Claude Code, Codex from AdvancingTitans/agent-engineering-toolkit. It costs 44 tokens per session (692 once invoked), scanned B, original, MIT.

A read-only investigation workflow for reviewing recorded coding-agent sessions and selected proof or freshness records. It answers one clearly stated question and packages the supporting evidence for another person to review.

In plain words
What is it for?
Use it to investigate agent behavior without changing the workspace, test a main hypothesis against an alternative, and export a portable evidence bundle. It can work with Codex or Claude Code run records.
Why use it?
It separates what a recorded run suggests from what has been explicitly verified. It also preserves competing explanations, unknowns, counter-evidence, and limits on what the evidence proves.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one. Also seen: mentions Claude Code; mentions Codex.

Good fit Use it to investigate agent behavior without changing the workspace, test a main hypothesis against an alternative, and export a portable evidence bundle. It can work with Codex or Claude Code run records.

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Install with agentmods
npx agentmods add skills/advancingtitans/agent-engineering-toolkit/aet-investigate
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 AdvancingTitans/agent-engineering-toolkit --skill aet-investigate
Clone the repo
git clone --depth 1 https://github.com/AdvancingTitans/agent-engineering-toolkit

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 aet-investigate

README.md
[![agentmods](https://agentmods.dev/badge/skills/advancingtitans/agent-engineering-toolkit/aet-investigate/github.svg)](https://agentmods.dev/skills/advancingtitans/agent-engineering-toolkit/aet-investigate)
Your own site
<a href="https://agentmods.dev/skills/advancingtitans/agent-engineering-toolkit/aet-investigate"><img src="https://agentmods.dev/badge/skills/advancingtitans/agent-engineering-toolkit/aet-investigate/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 aet-investigate

Your own site · 80×15
<a href="https://agentmods.dev/skills/advancingtitans/agent-engineering-toolkit/aet-investigate"><img src="https://agentmods.dev/badge/skills/advancingtitans/agent-engineering-toolkit/aet-investigate.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 44 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 692 The whole file, excluding the scripts and references it only reads on demand.
Security scan B 1 finding. 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 $0.00044 $0.00692
Opus 5.5 $0.00018 $0.00277
Sonnet 5.5 $0.00009 $0.00138
Haiku 4.5 $0.00004 $0.00069

Measured 2mo ago against content hash 20df7278b297, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade B, and why

aet-investigate scanned grade B with 1 finding 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 2mo 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.

Unrestricted tool accessmediumExcessive agency

A wildcard tool grant or "run any command" leaves no least-privilege boundary at all.

- Do not execute arbitrary commands, modify code, commit, push, merge, publish, or repair.
skills/aet-investigate/SKILL.md · 80 lines

How it starts

The opening of the file, as written. The whole thing — 80 lines — stays where its author put it; the contents beside it link to each section on GitHub.

/aet-investigate

Answer one declared investigation question with a portable evidence handoff.

Boundary

  • Keep the target workspace read-only.
  • Do not execute arbitrary commands, modify code, commit, push, merge, publish, or repair.
  • Require one primary hypothesis, at least one competing hypothesis, and a disconfirming search.
  • Treat Run Records as historical behavior. They may create Observations and Evidence Candidates, but only explicit proof.inspect and freshness.check results may create Verified Evidence.
  • Preserve unknown, counter-evidence, diagnostics, Freshness limitations, and every does_not_prove statement.
  • Use policy.json and tool-contract.json without expanding their authority.

Workflow

  1. Normalize one declared run when a normalized directory is not already available:

    aet run normalize --source <codex|claude-code> \
      --input <session.jsonl> --output <normalized-run>
    
  2. Create an investigation-request/1.0 JSON object. Bind its run_sources entry to the normalized Manifest's source_type and run_group_id. Copy the budgets and privacy boundary from policy.json; narrow them when possible.

  3. Run the investigator. Without a Proof it remains observation-only:

    aet investigate --request <request.json> \
      --run <normalized-run> --output <investigation.json>
    

    To inspect an existing deterministic Proof, the Policy must allow proof.inspect and freshness.check, and their budgets must be non-zero:

    aet investigate --request <request.json> \
      --run <normalized-run> --workspace <workspace> \
      --proof <proof.json> --output <investigation.json>
    

    The Proof path and its recorded workspace must remain inside and match the declared read-only workspace. A matching recorded command Candidate may be marked verified; stale Proof remains historical Evidence and cannot answer a current-workspace Claim.

  4. Compile and validate the handoff:

Read the full file on GitHub · 80 lines

Files

What ships with it

3 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

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. 2mo ago First seen · 80 lines · 44 tokens per session scan B 20df7278b297

Subscribe to this mod's changes

aet-investigate is a skill published in the GitHub repository AdvancingTitans/agent-engineering-toolkit (2 stars, last pushed 2mo ago), licensed MIT. It adds 44 tokens to every session and 692 once invoked, about $0.0002 per session on Opus 5.5. A static security scan graded it B with 1 finding (unrestricted tool access). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.

Related

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