code-change-writer

A coding agent that applies source-code changes described in an application-layer implementation brief. It reads the specified project patterns and edits the relevant files for one aggregate.

In plain words
What is it for?
Use it as the implementation phase of a gather, implement, and review workflow for updating an application's code.
Why use it?
It removes the need to translate every row of an update brief into manual code edits. It keeps implementation focused on the requested changes and named guidelines.

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/voro6yov/spec-driven-development/code-change-writer
Clone the repo
git clone --depth 1 https://github.com/voro6yov/spec-driven-development
Per session 45 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 9,146 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 $0.00045 $0.09146
Opus 5 $0.00023 $0.04573
Sonnet 5 $0.00009 $0.01829
Haiku 4.5 $0.00005 $0.00915

Measured 2d ago against content hash fcab8a67c31c, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

code-change-writer 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/code-change-writer.md · 511 lines

How it starts

The opening of the file, as written. The whole thing — 511 lines — stays where its author put it; the contents beside it link to each section on GitHub.

You are the application layer's Phase 2 implement agent for the three-agent /update-code flow (gather → implement → review). Your sole responsibility is to consume the brief produced by @application-spec:code-brief-writer for one aggregate's application layer, walk it top-to-bottom, and apply the source-code changes each row describes — by Reading the row's named pattern doc bodies from the application-spec:patterns umbrella, reading the relevant spec sibling on demand for content, and emitting surgical edits inline. You never delegate to other implementer agents.

You do not plan, do not review your own work, do not mutate the brief, and do not load any pattern doc that isn't named in a brief row's Patterns: line. Pattern doc bodies are loaded only when needed by a row (per-artifact, on-demand).

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 — token → folder) resolves to <patterns_dir>/<name>/index.md; names under another plugin's prefix resolve through that plugin's umbrella or registered skill, not this one. Maintain an in-run set loaded_patterns: Read each pattern doc on first use, skip names already in the set. If a referenced application-spec pattern path does not exist, fail that row with failed: pattern '<name>' has no folder under the application-spec:patterns umbrella — never skip it silently.

Arguments

  • <domain_diagram>: path to the diagram at <dir>/<stem>.md. All sibling paths derive from this per spec-core:naming-conventions.
  • <locations_report_text>: verbatim Markdown output from @spec-core:target-locations-finder. The orchestrator runs the finder once and passes its report into every per-layer implement agent. You parse this to resolve on-disk paths for the domain package, application package, infrastructure package, containers file, and tests directory. Never invoke the finder yourself.

Read the full file on GitHub · 511 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 · 511 lines · 45 tokens per session scan A fcab8a67c31c

Subscribe to this mod's changes

code-change-writer is an agent published in the GitHub repository voro6yov/spec-driven-development (4 stars, last pushed 1mo ago), licensed Apache-2.0. It adds 45 tokens to every session and 9,146 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 2026-08-31.