extend-skill

extend-skill is a skill for Claude Code, Codex from neat-technologies/neat. It costs 106 tokens per session (1,160 once invoked), scanned A, original, Apache-2.0.

A set of six tools for inspecting and changing instrumentation, which is extra code that records or exposes what a library is doing. The tools are designed for an AI agent to reason about extensions while keeping changes scoped and reversible.

In plain words
What is it for?
Use it to list uninstrumented projects, look up available instrumentation packages, describe current instrumentation, dry-run an extension, apply it, or roll it back.
Why use it?
It lets agents find missing instrumentation, preview changes, apply one extension at a time, and undo an extension without giving the instrumentation system its own language model.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit Use it to list uninstrumented projects, look up available instrumentation packages, describe current instrumentation, dry-run an extension, apply it, or roll it back.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/neat-technologies/neat/extend
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 neat-technologies/neat --skill extend
Clone the repo
git clone --depth 1 https://github.com/neat-technologies/neat

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 extend-skill

README.md
[![agentmods](https://agentmods.dev/badge/skills/neat-technologies/neat/extend.svg)](https://agentmods.dev/skills/neat-technologies/neat/extend)
Your own site
<a href="https://agentmods.dev/skills/neat-technologies/neat/extend"><img src="https://agentmods.dev/badge/skills/neat-technologies/neat/extend.svg" alt="Measured on agentmods" height="20"></a>
Per session 106 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,160 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 $0.00106 $0.01160
Opus 5 $0.00053 $0.00580
Sonnet 5 $0.00021 $0.00232
Haiku 4.5 $0.00011 $0.00116

Measured 3d ago against content hash e3e93577205f, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-07, from the pricing page.

Security

Grade A, and why

extend-skill 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 3d 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.

docs/contracts/extend-skill.md · 59 lines

How it starts

The opening of the file, as written. The whole thing — 59 lines — stays where its author put it; the contents beside it link to each section on GitHub.

/neat extend skill contract

/neat extend exposes NEAT's instrumentation surface to the user's MCP-capable agent as surgical tools. The agent provides intelligence; NEAT provides scoped, reversible primitives. This contract supersedes ADR-081's standalone-CLI and operator-LLM-key portions per ADR-086.

1. Six tools, two roles

Diagnostic (read-only): neat_list_uninstrumented(project), neat_lookup_instrumentation(library, installed_version?), neat_describe_project_instrumentation(project).

Operative (mutate the instrumentation surface): neat_apply_extension(library, instrumentation_package, version, registration_snippet), neat_dry_run_extension(...), neat_rollback_extension(library).

Each operative tool does exactly one thing. No macro tool applies multiple extensions in one call.

2. NEAT holds no LLM key; the agent reasons

There is no NEAT_LLM_API_KEY and no LLM call originating from NEAT during the skill's execution. Registry hits resolve deterministically through the registry loader (see instrumentation-registry.md). Registry misses are reasoned about by the agent's own model; the agent drafts a proposal and the user confirms via neat_dry_run_extension before any neat_apply_extension call.

3. No standalone CLI variant

Users without an MCP agent get the deterministic npx neat.is install. Extension requires an MCP-capable agent. There is no npx @neat.is/instrument fallback.

4. File-scope restricted

Operative tools modify only instrumentation*.ts / otel-init*, .env.neat, package.json, and the lockfile (via the project's package manager). Any write attempt outside this surface returns an error.

5. Idempotent, reversible, observable

apply called twice with the same args is a no-op the second time. Every apply logs its diff to ~/.neat/extend-log.ndjson so rollback can undo it. Apply returns the exact files touched, deps added, and install-command output.

6. NEAT never auto-applies

Read the full file on GitHub · 59 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. 3d ago First seen · 59 lines · 106 tokens per session scan A e3e93577205f

Subscribe to this mod's changes

extend-skill is a skill published in the GitHub repository neat-technologies/neat (18 stars, last pushed today), licensed Apache-2.0. It adds 106 tokens to every session and 1,160 once invoked, about $0.0005 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 2026-09-04.

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