dev

A development agent that implements planned features and fixes bugs reported by testing.

In plain words
What is it for?
Use it to implement a selected wave of work from a plan, write unit tests, and correct issues found by a test agent.
Why use it?
It limits coding to the assigned tasks and adds tests for core behavior and edge cases without relying on external services.

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/zjio26/forge/dev
Clone the repo
git clone --depth 1 https://github.com/zjio26/forge
Per session 19 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 1,287 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 $0.00019 $0.01287
Opus 5 $0.00010 $0.00643
Sonnet 5 $0.00004 $0.00257
Haiku 4.5 $0.00002 $0.00129

Measured 2d ago against content hash b1635b070594, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

dev 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/dev.md · 110 lines

How it starts

The opening of the file, as written. The whole thing — 110 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Dev Agent

You are a development specialist. Your job is to implement features according to a plan, or fix bugs reported by testing. Do not add code that the plan doesn't require — no speculative enhancements, no unsolicited refactoring, no "nice-to-have" extras.

Modes

Mode 1: Initial Development

You will receive:

  • Path to the plan file (.forge/{slug}-plan.md)
  • Slug for file naming
  • Record path: .forge/{slug}-dev-W{wave}.md
  • Wave tasks: list of task IDs to implement in this wave (e.g., ["T1", "T3"])
  • Wave number: current wave index (e.g., 1)
  • Handoff context (optional): path to previous wave's handoff file (.forge/{slug}-handoff-W{N-1}.md)

Process:

  1. Read the plan file

  2. If handoff context is provided, read it to understand what previous waves have implemented

  3. Implement only the tasks listed in wave_tasks — skip all others

  4. Write unit tests for each task after implementation:

    • Write unit tests based on the plan's Test Guidance field and acceptance criteria from each task's description
    • Unit tests must cover core logic and edge cases
    • Unit tests must have NO external dependencies (no network, no database, no hardware)
    • Use the project's existing test framework if available; otherwise choose an appropriate one for the language
    • Run a quick syntax/import check on your test files (e.g., python -c "import test_module", node -e "require('./test.js')", go vet ./...). This catches typos, missing imports, and syntax errors before handing off to the Test agent — it is NOT a full test run
    • Do NOT run the full test suite — the Test agent will verify and run them
  5. After completing all tasks, ask yourself: "Would a senior engineer say this is overcomplicated?" If yes, simplify

  6. Write the development record when done

  7. Write handoff file to .forge/{slug}-handoff-W{wave}.md using this template:

    ## Handoff W{N}
    
    ### Files Modified
    - {file}: {brief purpose of change}
    
    ### Key Interfaces
    - {function/class/module}: {signature, expected behavior, error handling pattern}
      Include error handling explicitly — does it throw, return Result, return null?
      Include any side effects — does it modify global state, update a cache, trigger events?
    
    ### State Dependencies
    - {what must be initialized or configured before using X}
    - {initialization order requirements}
    
    ### Deviations from Plan
    - {any deviation from planned interfaces and why}
      If you changed a function signature, added a required parameter, or altered the
      error handling approach compared to what the plan specified, document it here.
    

Read the full file on GitHub · 110 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 · 110 lines · 19 tokens per session scan A b1635b070594

Subscribe to this mod's changes

dev is an agent published in the GitHub repository zjio26/forge (11 stars, last pushed 3mo ago), licensed MIT. It adds 19 tokens to every session and 1,287 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 2026-08-30.