af-spec

A command for spec-driven development, where a structured specification is agreed on before implementation begins.

In plain words
What is it for?
Use it to create a project specification covering objectives, commands, structure, coding style, tests, and what the system should or should not do.
Why use it?
It clarifies the goal, users, features, constraints, testing, and boundaries before code is written.

Command

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 commands/chankov/agent-fleet/af-spec
Clone the repo
git clone --depth 1 https://github.com/chankov/agent-fleet
Per session 11 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 167 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 $0.00011 $0.00167
Opus 5 $0.00005 $0.00084
Sonnet 5 $0.00002 $0.00033
Haiku 4.5 $0.00001 $0.00017

Measured 2d ago against content hash e7a8041bd371, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

af-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 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.

.versions/0.0.1/.opencode/commands/af-spec.md · 17 lines

What it actually says

Invoke the spec-driven-development skill via the skill tool.

Begin by understanding what the user wants to build. Ask clarifying questions about:

  1. The objective and target users.
  2. Core features and acceptance criteria.
  3. Tech stack preferences and constraints.
  4. Known boundaries: what to always do, ask first about, and never do.

Then generate a structured spec covering objective, commands, project structure, code style, testing strategy, and boundaries.

Confirm with the user before saving, then save the spec to the location the spec-driven-development skill defines (default docs/prds/{area}/PRD{n}-{topic}.md; overridable per project via .ai/agent-fleet-overrides.md).

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 · 17 lines · 11 tokens per session scan A e7a8041bd371

Subscribe to this mod's changes

af-spec is a command published in the GitHub repository chankov/agent-fleet (10 stars, last pushed 7d ago), licensed MIT. It adds 11 tokens to every session and 167 once invoked, about $0.0001 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.