sdd-reverse-scout

sdd-reverse-scout is an agent for Claude Code from GregorBiswanger/featherspec. It costs 44 tokens per session (316 once invoked), scanned A, original, MIT.

A restricted research agent that reads code for one capability and writes an evidence report with file and line references. It records observed behaviour rather than intended behaviour and does not run commands or build the project.

In plain words
What is it for?
Use it as part of a workflow that documents what an existing capability actually does.
Why use it?
It gives a reverse-specification workflow traceable evidence from the code instead of assumptions based on names, comments, or test titles.

Agent for Claude Code

Written for Claude Code: installed under .claude/. Also seen: reads .claude/ paths.

Good fit Use it as part of a workflow that documents what an existing capability actually does.

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Install with agentmods
npx agentmods add agents/gregorbiswanger/featherspec/sdd-reverse-scout
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.

Clone the repo
git clone --depth 1 https://github.com/GregorBiswanger/featherspec

Made for: Claude Code.

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 sdd-reverse-scout

README.md
[![agentmods](https://agentmods.dev/badge/agents/gregorbiswanger/featherspec/sdd-reverse-scout/github.svg)](https://agentmods.dev/agents/gregorbiswanger/featherspec/sdd-reverse-scout)
Your own site
<a href="https://agentmods.dev/agents/gregorbiswanger/featherspec/sdd-reverse-scout"><img src="https://agentmods.dev/badge/agents/gregorbiswanger/featherspec/sdd-reverse-scout/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 sdd-reverse-scout

Your own site · 80×15
<a href="https://agentmods.dev/agents/gregorbiswanger/featherspec/sdd-reverse-scout"><img src="https://agentmods.dev/badge/agents/gregorbiswanger/featherspec/sdd-reverse-scout.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 44 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 316 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 $0.00044 $0.00316
Opus 5.5 $0.00018 $0.00126
Sonnet 5.5 $0.00009 $0.00063
Haiku 4.5 $0.00004 $0.00032

Measured 20d ago against content hash 1ba6ac3ee60e, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

sdd-reverse-scout 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 20d 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.

.claude/agents/sdd-reverse-scout.md · 21 lines

What it actually says

You are the evidence scout for this repository's /sdd-reverse-specify workflow. You investigate exactly one capability per invocation, through the lens the delegation names; the delegation message carries the capability, its entry points, the lens, the report path, the schema, the read budget and DocLanguage — follow it precisely. Read and search only — run no commands and build nothing. Report what the code does, each statement with its path:line: never why, never what was intended, and never a value you did not read in the code. A name, a comment or a test title is a hypothesis — confirm it in a body before you state it. Write only inside .sdd-reverse/reports/. If the capability is too large for one honest report, return a structural note proposing sub-capabilities instead of a thinner report. Return at most five summary lines.

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. 20d ago First seen · 21 lines · 44 tokens per session scan A 1ba6ac3ee60e

Subscribe to this mod's changes

sdd-reverse-scout is an agent published in the GitHub repository GregorBiswanger/featherspec (66 stars, last pushed 19d ago), licensed MIT. It adds 44 tokens to every session and 316 once invoked, about $0.0002 per session on Opus 5.5. 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 2026-09-26.