discover

A workflow for expanding a contextualizer’s reference library, where a contextualizer is a project skill that supplies background files to an AI assistant. It discovers important information in registered sources and writes reference files for it.

In plain words
What is it for?
Use it for a first pass on a new contextualizer, periodic upkeep, or proposing reference files when existing sources no longer cover important requests.
Why use it?
It helps keep the assistant’s reference material aligned with what users ask about instead of letting the catalogue become outdated.

Skill for Claude CodeCodex

Part of the skill-engine plugin — 12 skills shipped together

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.

agentmods
npx agentmods add skills/nick-railsback/skill-engine/discover
Any agent
npx skills add nick-railsback/skill-engine --skill discover
Clone the repo
git clone --depth 1 https://github.com/nick-railsback/skill-engine

Made for: Claude Code, Codex.

Or install skill-engine, the plugin that ships this one along with the rest of its 12 skills.

Per session 47 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,921 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
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 $0.00047 $0.01921
Opus 5 $0.00023 $0.00960
Sonnet 5 $0.00009 $0.00384
Haiku 4.5 $0.00005 $0.00192

Measured 2d ago against content hash 18097c0f3855, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

discover 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 2d 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.

plugin/skill-engine/skills/discover/SKILL.md · 176 lines

How it starts

The opening of the file, as written. The whole thing — 176 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Discover

You receive a task: discover the essence of the registered sources, then write reference files for the parts that matter. The named checks in verify.sh (plus the permalink-density lint for SHA-pinning) validate your output; the four reference invariants are your authoring targets — not all are machine-checked (see § Output contract). How you reason about the corpus is your call — there is no Stage 0/1/2 prescription, no fixed keystroke menu, no required worker dispatch. Vary your approach by what the corpus rewards.

Contextualizer root

Engine workflows operate inside a contextualizer installed as a project skill at one of three install levels:

  • User-level: ~/.claude/skills/<slug>-context/
  • Local-user-level: ~/.claude/local/skills/<slug>-context/ (when in use)
  • Project-level: <repo>/.claude/skills/<slug>-context/

Every path below — research/..., references/..., verify.sh — resolves relative to whichever directory matches. Before reading or writing anything, locate the root by searching all three install levels in order:

Run the script in shared/locator-block.md verbatim before proceeding.

CTX_PROPOSED="${CTX_ROOT}.proposed"

Multi-contextualizer disambiguation and the full staging-directory model — the $CTX_PROPOSED manifest schema, removed-detection, and the review/apply/discard handoff — are documented in references/staging-and-contextualizer-model.md. Read it before your first write of a run, or whenever more than one contextualizer is found.

Output contract

Two things, both load-bearing:

  1. Reference files in references/. Each cites its source by path plus content-hash (see 02-artifact-contract.md). Each satisfies the four reference invariants (definitions owned by 02-artifact-contract.md §Navigator size budget and §Long references — do not restate them elsewhere):
    • first-5K — the navigator's standing instructions (invariants, critical rules, dispatch logic) fit in the first 5K bytes of SKILL.md body; the catalog table is a TOC and is exempt.
    • depth-1 — no more than one level of pointer indirection.
    • max-100-line-TOC — any reference body over 100 lines carries a TOC marker within its first 30 lines.
    • SHA-pin — every citation pins to a specific SHA, not a moving branch or tag.
  2. A post-run summary for the author (see "Post-run summary" below).

Read the full file on GitHub · 176 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. 2d ago First seen · 176 lines · 47 tokens per session scan A 18097c0f3855

Subscribe to this mod's changes

discover is a skill published in the GitHub repository nick-railsback/skill-engine (2 stars, last pushed 26d ago), licensed MIT. It adds 47 tokens to every session and 1,921 once invoked, about $0.0002 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 2026-08-31.

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