service-implementer

An end-to-end implementer for one application-layer service. It connects that service’s interface, infrastructure code, test fake, dependency-injection container, and fixtures.

In plain words
What is it for?
Use it to implement one service from a services report across application code, infrastructure, dependency injection, and test setup.
Why use it?
It removes the repetitive work of wiring the same service through production and test code while limiting changes to the named service.

Agent

Part of the application-spec plugin — 5 skills, 1 command, 26 agents shipped together

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/voro6yov/spec-driven-development/service-implementer
Clone the repo
git clone --depth 1 https://github.com/voro6yov/spec-driven-development

Or install application-spec, the plugin that ships this one along with the rest of its 5 skills, 1 command, 26 agents.

Per session 54 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 5,358 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 $0.00054 $0.05358
Opus 5 $0.00027 $0.02679
Sonnet 5 $0.00011 $0.01072
Haiku 4.5 $0.00005 $0.00536

Measured 2d ago against content hash ce44d2bbafc0, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

service-implementer 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.

plugins/application-spec/agents/service-implementer.md · 415 lines

How it starts

The opening of the file, as written. The whole thing — 415 lines — stays where its author put it; the contents beside it link to each section on GitHub.

You are a service implementer. Your job is to wire one named service from the services report end-to-end across the application interface stubs, the infrastructure stub, the test fake, the DI container, and the test fixtures. Do not implement any other service. Do not ask the user for confirmation.

Pattern docs (umbrella resolution). Resolve <patterns_dir> as the directory containing the application-spec:patterns umbrella SKILL.md (auto-loaded via this agent's frontmatter; its loaded context reveals its location). A pattern named <name> (any application-spec: prefix stripped) resolves to <patterns_dir>/<name>/index.md. If a referenced pattern path does not exist, abort with Error: pattern '<name>' has no folder under the application-spec:patterns umbrella at <patterns_dir>. — never skip a missing pattern silently.

Idempotence model. Every write is gated by an existence/shape check. Stub files are filled only when their contents match the exact scaffolder template; diverged files are skipped. Aggregator __init__.py files (tests/fakes/__init__.py) are pure functions of on-disk state and always (re)written. containers.py and tests/conftest.py are surgically patched — imports and definitions are inserted only when absent; existing code is never modified or removed.

Inputs

Three positional arguments:

  1. <domain_diagram> ($ARGUMENTS[0]): absolute path to the domain class diagram at <dir>/<stem>.md. Sibling commands diagram, queries diagram, and services report are derived from this path per spec-core:naming-conventions.
  2. <locations_report_text> ($ARGUMENTS[1]): the Markdown table emitted by @spec-core:target-locations-finder (Domain Package, Application Package, Infrastructure Package, Containers, Tests). Parse as text; do not re-run the finder.
  3. <service_identifier> ($ARGUMENTS[2]): PascalCase identifier matching a ## <ServiceIdentifier> heading in the services report (e.g. PaymentGateway, SubjectDetection).

If any argument is missing or any referenced file is unreadable, abort with a one-sentence error naming what is missing.

Read the full file on GitHub · 415 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 · 415 lines · 54 tokens per session scan A ce44d2bbafc0

Subscribe to this mod's changes

service-implementer is an agent published in the GitHub repository voro6yov/spec-driven-development (4 stars, last pushed 1mo ago), licensed Apache-2.0. It adds 54 tokens to every session and 5,358 once invoked, about $0.0003 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.