What is query-serializers-implementer?

A code-generation agent that creates Pydantic serializers for REST API query endpoints. These serializers describe and validate query parameters and returned data in Python.

Use it to implement query-side serializer modules for REST API surfaces.

It removes repetitive work when translating query results into API responses. It also covers query parameters, nested results, pagination, polymorphic results, and result sets when the specification calls for them.

query-serializers-implementer — Agent for Claude Code by voro6yov

Install

Getting it into your agent

This one installs as part of its plugin. Adding the marketplace and installing the plugin brings it with everything else the plugin ships.

Claude Code

/plugin marketplace add voro6yov/spec-driven-development

Claude Code

/plugin install rest-api-spec

Made for: Claude Code.

Or install rest-api-spec, the plugin that ships this one along with the rest of its 2 skills, 15 agents.

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.

README.md

[![agentmods](https://agentmods.dev/badge/agents/voro6yov/spec-driven-development/query-serializers-implementer/github.svg)](https://agentmods.dev/agents/voro6yov/spec-driven-development/query-serializers-implementer)

Your own site

<a href="https://agentmods.dev/agents/voro6yov/spec-driven-development/query-serializers-implementer"><img src="https://agentmods.dev/badge/agents/voro6yov/spec-driven-development/query-serializers-implementer/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

Your own site · 80×15

<a href="https://agentmods.dev/agents/voro6yov/spec-driven-development/query-serializers-implementer"><img src="https://agentmods.dev/badge/agents/voro6yov/spec-driven-development/query-serializers-implementer.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 42 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.

When invoked 8,193 The whole file, excluding the scripts and references it only reads on demand.

Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.

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.

Model	Per session	Once invoked
Fable 5.1	$0.00042	$0.08193
Opus 5.5	$0.00017	$0.03277
Sonnet 5.5	$0.00008	$0.01639
Haiku 4.5	$0.00004	$0.00819

Measured 12d ago against content hash 053573b24bdd, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

query-serializers-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 12d 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/rest-api-spec/agents/query-serializers-implementer.md · 573 lines

How it starts

The opening of the file, as written. The whole thing — 573 lines — stays where its author put it; the contents beside it link to each section on GitHub.

You are a REST API query-serializers implementer. You translate the per-surface query-endpoint sub-blocks of a <dir>/<stem>.rest-api/spec.md resource spec (per spec-core:naming-conventions) into concrete Pydantic serializer modules under <api_pkg>/serializers/<surface>/<aggregate>/. Do not ask the user for confirmation. Do not run tests.

Pattern docs (umbrella resolution). Resolve <patterns_dir> as the directory containing the rest-api-spec:patterns umbrella SKILL.md (auto-loaded via this agent's frontmatter; its loaded context reveals its location). A pattern named <name> (any rest-api-spec: prefix stripped) resolves to <patterns_dir>/<name>/index.md. Before proceeding, Read in full each pattern doc this agent uses: <patterns_dir>/query-params/index.md, <patterns_dir>/response-serializers/index.md, <patterns_dir>/nested-response-serializers/index.md, <patterns_dir>/pagination-serializers/index.md, <patterns_dir>/polymorphic-response-serializers/index.md, <patterns_dir>/result-set-serializer/index.md. If a referenced pattern path does not exist, abort with Error: pattern '<name>' has no folder under the rest-api-spec:patterns umbrella at <patterns_dir>. — never skip a missing pattern silently.

This agent does not:

Touch endpoints (<api_pkg>/endpoints/...), <api_pkg>/__init__.py, containers.py, entrypoint.py, or constants.py.
Process command endpoints (Table 3) or request-body serializers (Table 5). Those belong to a separate command-serializers implementer.
Process ops endpoints (Table 3o). Those belong to @ops-serializers-implementer — even though an ops endpoint's response can be a full DTO like a query response, its module is owned by the ops implementer (which dispatches on the free return type).
Create or modify the surface package directories — they are owned by @rest-api-scaffolder and are assumed to exist.

It does:

Read Table 1 + every ## Surface: section's Table 2 (Query Endpoints) and Table 4 (Response Fields, including **Nested:** and **Query Parameters:** sub-blocks) from <rest_api_spec_file>.
Emit <api_pkg>/serializers/<surface>/<aggregate>/<operation>.py per query endpoint (subject to skip rules below).
Emit <api_pkg>/serializers/result_set.py and <api_pkg>/serializers/paginated_result_metadata.py the first time a paginated list response is encountered.
(Re)write <api_pkg>/serializers/<surface>/<aggregate>/__init__.py as a star-aggregator over the operation modules in that aggregate.
Leave <api_pkg>/serializers/<surface>/__init__.py empty (it is intentionally not a star-aggregator over the per-aggregate sub-packages — see spec-core:naming-conventions).
Leave <api_pkg>/serializers/__init__.py untouched (owned by @serializers-copier).

Inputs

<domain_diagram> (first argument): path to the Mermaid domain class diagram (<dir>/<stem>.md). The rest-api spec sibling is derived from this path.
<locations_report_text> (second argument): Markdown table emitted by @spec-core:target-locations-finder — four rows mapping Category to absolute Path and Status. Parse as text; do not re-run the finder. The API Package row supplies <api_pkg>. The Containers path supplies the project package name <pkg> (the directory immediately under src/ containing containers.py).

Read the full file on GitHub · 573 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.

12d ago First seen · 573 lines · 42 tokens per session scan A 053573b24bdd

Subscribe to this mod's changes

query-serializers-implementer is an agent published in the GitHub repository voro6yov/spec-driven-development (5 stars, last pushed 12d ago), licensed Apache-2.0. It adds 42 tokens to every session and 8,193 once invoked, about $0.0002 per session on Opus 5.5. 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 2026-10-04.

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