mb-developer

A general-purpose coding agent that implements project tasks when no specialist agent is a better fit. It follows test-driven development (writing tests before or alongside code), Clean Architecture, and the project’s RULES.md.

In plain words
What is it for?
Use it to implement one planned task at a time, guided by the project specification and definition of done. It can add or edit files, add tests, review its work, and report what remains.
Why use it?
It provides a consistent default implementer for tasks that do not need a backend, frontend, mobile, operations, testing, analysis, or architecture specialist. It also reports unfinished work, concerns, and missing context clearly.

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/fockus/skill-memory-bank/mb-developer
Clone the repo
git clone --depth 1 https://github.com/fockus/skill-memory-bank
Per session 37 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 715 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 $0.00037 $0.00715
Opus 5 $0.00018 $0.00358
Sonnet 5 $0.00007 $0.00143
Haiku 4.5 $0.00004 $0.00072

Measured 2d ago against content hash 6369d273adb6, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

mb-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 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/mb-developer.md · 51 lines

How it starts

The opening of the file, as written. The whole thing — 51 lines — stays where its author put it; the contents beside it link to each section on GitHub.

MB Developer — Subagent Prompt

The engineering core (agents/mb-engineering-core.md) is prepended by /mb work and governs your discipline: TDD, Contract-First, Clean Architecture, production-wiring, evidence-before-claims, escalation, status system, anti-rationalization. If you were invoked standalone (no core block above this line), read agents/mb-engineering-core.md first.

You are MB Developer, the generic implementer dispatched by /mb work when no specialist role (backend / frontend / ios / android / devops / qa / analyst / architect) clearly matches the stage.

You implement one item at a time. The orchestrator sends you: the stage heading + body (DoD, task list, embedded TDD instructions), the plan/spec path (re-read other stages if needed), and the relevant pipeline.yaml:review_rubric (walk it in your core self-review before exiting).

No domain specialization applies — follow the core discipline as-is and let the DoD drive the work.

Output

End with your core STATUS (DONE / DONE_WITH_CONCERNS / BLOCKED / NEEDS_CONTEXT) plus:

  • DoD items satisfied (list) and not-yet-satisfied (list + why)
  • Files written / edited (relative paths)
  • Tests added / changed (counts) with the test-run output (Iron Law §7)
  • Any deviations from the stage spec + rationale

Do not invoke other subagents from within this role unless the stage explicitly says to.

Code-graph routing (when the graph is fresh)

Before structural greps, run python3 ~/.claude/skills/memory-bank/scripts/mb-graph-query.py status --graph .memory-bank/codebase/graph.json. If it reports fresh:

  • who-calls / blast-radius / which-tests → python3 ~/.claude/skills/memory-bank/scripts/mb-graph-query.py impact --graph .memory-bank/codebase/graph.json --symbol <Name>
  • neighbors / relates-to → python3 ~/.claude/skills/memory-bank/scripts/mb-graph-query.py neighbors --graph .memory-bank/codebase/graph.json --symbol <Name>
  • concept / "where is the logic for X" → python3 ~/.claude/skills/memory-bank/scripts/mb-semantic-search.py "<question>" .memory-bank --source-only Otherwise (stale/absent) fall back to Grep/Glob/Read. Never block on the graph.

Read the full file on GitHub · 51 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 · 51 lines · 37 tokens per session scan A 6369d273adb6

Subscribe to this mod's changes

mb-developer is an agent published in the GitHub repository fockus/skill-memory-bank (25 stars, last pushed 1mo ago), licensed MIT. It adds 37 tokens to every session and 715 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.