spec

A planning procedure that turns a complex software change into an agreed implementation contract. It researches the repository, records interfaces and constraints, and stops before coding for approval.

In plain words
What is it for?
Use it to plan non-trivial changes with repository research, defined file or code interfaces, acceptance criteria, and explicit approval.
Why use it?
It exposes unknowns, dependencies, and security requirements before implementation begins.

Skill for Claude CodeCodex

Part of the neural plugin — 9 skills, 3 hooks 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/brolag/neural-claude-code/spec
Any agent
npx skills add brolag/neural-claude-code --skill spec
Clone the repo
git clone --depth 1 https://github.com/brolag/neural-claude-code

Made for: Claude Code, Codex.

Or install neural, the plugin that ships this one along with the rest of its 9 skills, 3 hooks.

Per session 69 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,229 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 $0.00069 $0.01229
Opus 5 $0.00034 $0.00615
Sonnet 5 $0.00014 $0.00246
Haiku 4.5 $0.00007 $0.00123

Measured 3d ago against content hash f34a9feb142f, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

spec 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.

skills/spec/SKILL.md · 124 lines

How it starts

The opening of the file, as written. The whole thing — 124 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Spec

Turn intent and repository evidence into an approvable implementation contract. Never write implementation code.

This skill is the Claude Code port of the Neural Codex spec gate. Same contract, slash invocation.

1. Right-size and research

Skip ceremony for an obvious change under roughly 25 lines with no new interface, ambiguity, or risk.

Otherwise:

  1. Find the newest related plans/**/unknowns-map.md and read it first.
  2. Read repository guidance, the relevant code, tests, documentation, and useful history.
  3. Reuse established patterns before proposing new ones.
  4. If discovery was skipped, record that fact and clarify only architecture-changing ambiguity (AskUserQuestion, at most 3).

Treat resolved discovery decisions as inputs. Preserve unresolved blockers instead of guessing around them.

If the user cannot yet say what "good" looks like, route to /discover instead of guessing a plan.

2. Lock the contract

Declare every introduced or changed interface before implementation:

name(parameters) -> result [new|adapt|reuse] -> path

Interfaces include functions, types, commands, files, routes, events, schemas, and durable artifact shapes. A new interface that duplicates an existing one is a planning defect.

For every relevant security or trust boundary, add an @invariant with its CWE and concrete mitigation. Cover path handling, secret exposure, command execution, authorization, destructive side effects, and validation integrity when applicable.

Keep every invariant testable at its boundary. Do not treat a general security promise as a replacement for a concrete mitigation and verification command.

3. Decompose and route

Give every subtask a stable ID and a [tier:] model-routing tag:

  • cheap: mechanical edits, boilerplate, and narrow tests
  • mid: normal implementation requiring local judgment
  • hard: architecture, security, ambiguity, or tricky debugging
  • batch: long-running multi-step or operational work

Add [needs: S1, S2] only for real dependencies. No dependency tag means the work may execute independently. Validate that every referenced ID exists and that the graph is acyclic.

Read the full file on GitHub · 124 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 · 124 lines · 69 tokens per session scan A f34a9feb142f

Subscribe to this mod's changes

spec is a skill published in the GitHub repository brolag/neural-claude-code (11 stars, last pushed 13d ago), licensed MIT. It adds 69 tokens to every session and 1,229 once invoked, about $0.0003 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 2026-08-30.

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