af-build

A command for implementing planned coding tasks one at a time. For each task, it writes a failing test, adds the smallest working implementation, runs checks, and marks the task complete.

In plain words
What is it for?
Use it to select the next pending task, read its acceptance criteria, write tests, implement the change, run tests and the build, and call the debugging workflow when something fails.
Why use it?
It provides a repeatable way to turn an accepted plan into tested code. Writing the test first makes the intended behavior explicit and helps catch regressions.

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-build
Clone the repo
git clone --depth 1 https://github.com/chankov/agent-fleet
Per session 14 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 159 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 $0.00014 $0.00159
Opus 5 $0.00007 $0.00079
Sonnet 5 $0.00003 $0.00032
Haiku 4.5 $0.00001 $0.00016

Measured 3d ago against content hash 780bbfb5158f, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

af-build 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.

.versions/0.0.1/.opencode/commands/af-build.md · 18 lines

What it actually says

Invoke the incremental-implementation skill and the test-driven-development skill via the skill tool.

Pick the next pending task from the plan. For each task:

  1. Read the task's acceptance criteria.
  2. Load relevant context: existing code, patterns, and types.
  3. Write a failing test for the expected behavior.
  4. Implement the minimum code to pass the test.
  5. Run the relevant test suite to check for regressions.
  6. Run the build to verify compilation.
  7. Mark the task complete and move to the next one.

If any step fails, invoke the debugging-and-error-recovery skill via the skill tool.

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 · 18 lines · 14 tokens per session scan A 780bbfb5158f

Subscribe to this mod's changes

af-build is a command published in the GitHub repository chankov/agent-fleet (10 stars, last pushed 7d ago), licensed MIT. It adds 14 tokens to every session and 159 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.