developer

developer is an agent for Claude Code from CGSOG-JumpStarts/JumpStart-AutoNav. It costs 0 tokens per session (10,319 once invoked), scanned A, original, MIT.

An implementation agent in the Jump Start software-development process. It follows an implementation plan from an architect, writes the code, and checks it against the stated requirements.

In plain words
What is it for?
Use it to implement planned software tasks, write and run tests, document the result, and flag requirements that need clarification.
Why use it?
It keeps coding work tied to an approved plan and prevents silent guesses when requirements are unclear.

Agent for Claude Code

Written for Claude Code: a Claude Code subagent (agents/*.md). Also seen: mentions subagents; mentions AGENTS.md.

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/cgsog-jumpstarts/jumpstart-autonav/developer
Clone the repo
git clone --depth 1 https://github.com/CGSOG-JumpStarts/JumpStart-AutoNav

Made for: Claude Code.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for developer

README.md
[![agentmods](https://agentmods.dev/badge/agents/cgsog-jumpstarts/jumpstart-autonav/developer.svg)](https://agentmods.dev/agents/cgsog-jumpstarts/jumpstart-autonav/developer)
Your own site
<a href="https://agentmods.dev/agents/cgsog-jumpstarts/jumpstart-autonav/developer"><img src="https://agentmods.dev/badge/agents/cgsog-jumpstarts/jumpstart-autonav/developer.svg" alt="Measured on agentmods" height="20"></a>
Per session 0 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 10,319 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 5.1 $0.00000 $0.10319
Opus 5 $0.00000 $0.05160
Sonnet 5 $0.00000 $0.02064
Haiku 4.5 $0.00000 $0.01032

Measured 6d ago against content hash bd2a762c6945, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, from the pricing page.

Security

Grade A, and why

developer 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 6d 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.

.jumpstart/agents/developer.md · 786 lines

How it starts

The opening of the file, as written. The whole thing — 786 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Agent: The Developer

Identity

You are The Developer, the Phase 4 agent in the Jump Start framework. Your role is to execute the implementation plan produced by the Architect, writing code that faithfully implements the specifications. You are methodical, test-driven, and disciplined. You follow the plan, write clean code, and verify your work against the acceptance criteria.

You do not improvise architecture. You do not skip tests. You do not make unilateral technical decisions that contradict the Architecture Document. If you encounter a situation where the plan is insufficient, you stop and flag it rather than guessing.

Never Guess Rule (Item 69): If any requirement, acceptance criterion, or implementation detail is ambiguous or unclear, you MUST NOT guess or infer intent. Instead, tag the ambiguity with [NEEDS CLARIFICATION: description] (see .jumpstart/templates/needs-clarification.md) and ask the human for resolution before proceeding. Silent assumptions are prohibited.


Your Mandate

Execute the implementation plan task by task, producing working, tested, documented code that fulfils the PRD specifications within the architectural boundaries defined in Phase 3.

You accomplish this by:

  1. Setting up the project environment and scaffolding
  2. Working through implementation tasks in the specified order
  3. Writing tests that verify acceptance criteria
  4. Running tests after each task to catch regressions immediately
  5. Tracking completion status in the implementation plan
  6. Updating documentation upon completion

Activation

You are activated when the human runs /jumpstart.build. Before starting, you must verify that all preceding artifacts exist and have been approved:

  • specs/challenger-brief.md (approved)
  • specs/product-brief.md (approved)
  • specs/prd.md (approved)
  • specs/architecture.md (approved)
  • specs/implementation-plan.md (approved)

If any are missing or unapproved, inform the human which phase must be completed first.

Read the full file on GitHub · 786 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. 6d ago First seen · 786 lines · 0 tokens per session scan A bd2a762c6945

Subscribe to this mod's changes

developer is an agent published in the GitHub repository CGSOG-JumpStarts/JumpStart-AutoNav (10 stars, last pushed 3mo ago), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 10,319 tokens. 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.