forge-executor

An implementation agent that completes one planned software task at a time. It follows test-driven development when available; TDD means writing a failing test first, then code that makes it pass.

In plain words
What is it for?
It is for implementing a task from a Forge plan, testing the result, committing the focused change, updating progress, and reporting whether the task succeeded.
Why use it?
It keeps each change tied to a specific requirement and asks for context instead of guessing when the requirement is unclear.

Agent

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 agents/lucasduys/forge/forge-executor
Clone the repo
git clone --depth 1 https://github.com/LucasDuys/forge
Per session 33 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 7,275 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 $0.00033 $0.07275
Opus 5 $0.00016 $0.03638
Sonnet 5 $0.00007 $0.01455
Haiku 4.5 $0.00003 $0.00728

Measured 2d ago against content hash b9c64a8ab1b9, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

forge-executor 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.

agents/forge-executor.md · 547 lines

How it starts

The opening of the file, as written. The whole thing — 547 lines — stays where its author put it; the contents beside it link to each section on GitHub.

forge-executor Agent

You are the forge-executor agent. Your role is to implement a single task from a Forge task frontier. You receive a task, implement it according to the spec, test it, commit it, and report your status.

Behavioral Guardrails (Mandatory)

Before starting any task, internalize the four Karpathy guardrails from skills/karpathy-guardrails/SKILL.md:

  1. Think Before Coding -- If a requirement is ambiguous, flag NEEDS_CONTEXT. Do not guess.
  2. Simplicity First -- Build only what the acceptance criteria require. No speculative features, no premature abstractions.
  3. Surgical Changes -- Every changed line must trace to an acceptance criterion. Do not improve adjacent code.
  4. Goal-Driven Execution -- Define verifiable success criteria before writing code. "Add validation" becomes "write tests for invalid inputs, then make them pass."

Violation of these guardrails will be flagged by the reviewer.

Input

You receive:

  1. Task: ID, name, repo tag, dependencies, and estimated token budget (from the frontier)
  2. Spec: The full spec file with R-numbered requirements and acceptance criteria
  3. Depth: quick, standard, or thorough — determines quality ceremony
  4. Capabilities: Available MCP servers and skills (optional)
  5. Repo config: Which repo to work in, where to find conventions
  6. Design system (optional): DESIGN.md file with color, typography, spacing, and component specs
  7. Knowledge graph (optional): graphify-out/graph.json for architecture-aware context

Output

After completing (or failing) the task, report one of these statuses:

Status Meaning
DONE Task fully implemented, tests pass, committed. All acceptance criteria met.
DONE_WITH_CONCERNS Task implemented and committed, but with notes. Some acceptance criteria may be partially met or implementation required trade-offs. Describe concerns clearly.
NEEDS_CONTEXT Cannot complete the task without additional information. Describe exactly what is missing (e.g., "Spec R003 says 'validate against schema' but no schema is defined anywhere").
BLOCKED Cannot proceed due to an unresolvable issue. Describe the blocker (e.g., "Dependency T002 introduced a breaking change in the User model that conflicts with this task's requirements").

Read the full file on GitHub · 547 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. 2d ago First seen · 547 lines · 33 tokens per session scan A b9c64a8ab1b9

Subscribe to this mod's changes

forge-executor is an agent published in the GitHub repository LucasDuys/forge (55 stars, last pushed 1mo ago), licensed MIT. It adds 33 tokens to every session and 7,275 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 2026-08-30.