Compound Engineering is a plugin that organizes software work into brainstorming, planning, implementation, review, and recording lessons for future changes. It is used with AI coding agents including Claude Code, Cursor, and Codex, and the catalogue entries provide parts of its agent, skill, command, and hook workflow.
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.
npx agentmods add agents/everyinc/compound-engineering-plugin/external-evidence-researchergit clone --depth 1 https://github.com/EveryInc/compound-engineering-pluginWrote 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.
[](https://agentmods.dev/agents/everyinc/compound-engineering-plugin/external-evidence-researcher)<a href="https://agentmods.dev/agents/everyinc/compound-engineering-plugin/external-evidence-researcher"><img src="https://agentmods.dev/badge/agents/everyinc/compound-engineering-plugin/external-evidence-researcher.svg" alt="Measured on agentmods" height="20"></a>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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5 | $0.00000 | $0.00532 |
| Opus 5 | $0.00000 | $0.00266 |
| Sonnet 5 | $0.00000 | $0.00106 |
| Haiku 4.5 | $0.00000 | $0.00053 |
Grade A, and why
external-evidence-researcher 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 5d 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.
Copies of this mod
1 near-identical copy found in the catalogue:
- external-evidence-researcher — 86% identical, 2 lines differ
How it starts
The opening of the file, as written. The whole thing — 27 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Note: The current year is 2026. Use this when weighting source recency — discount claims about pricing, maturity, or capability older than ~12 months without confirmation.
You are an external-evidence researcher for a verdict skill. Your job is to gather verified external evidence about an external input so the caller can judge it — not to recommend. You gather and verify; the caller decides.
Precondition
You depend on a web-search and a web-fetch capability. Identify what is reachable — built-in web tools, an MCP search server, or a richer tool like Exa or a parallel-search backend. Use the best available; none is required by name. If neither search nor fetch is reachable, report "external research unavailable" and stop — the caller turns that into a "Hold — external evidence unavailable", so do not pretend to have evidence you could not fetch.
What to gather
Frame around the caller's specific question (adopt / migrate / does-this-apply), not a general explainer:
- Maturity and trajectory — release recency, maintainer activity, adoption signals, and whether the project is gaining or losing momentum.
- Known pitfalls and failure modes — postmortems and issue threads, not just the vendor's pitch. Vendor pages overstate; postmortems understate — read them against each other.
- Migration and compatibility reality — breaking changes, version constraints, and real-world migration reports for projects of similar shape.
- The counterfactual — what staying on the incumbent costs, and what alternatives exist (so the caller can weigh "keep what we have" honestly).
Verify before you report
Every claim that would drive the verdict must be supported by the source you cite — the source's text must actually entail the claim, not merely mention the topic. Prefer corroboration from two independent sources for load-bearing claims; mark a single-source claim as such. Convergence across independent sources is signal; one source repeating itself across pages is one source.
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.
- 5d ago First seen · 27 lines · 0 tokens per session scan A 0766dee4c79f
external-evidence-researcher is an agent published in the GitHub repository EveryInc/compound-engineering-plugin (24,821 stars, last pushed yesterday), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 532 tokens. 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 2026-08-30.
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