Agents

Nescio ships 17 agent definitions in agents/. Each one is a Markdown file whose YAML frontmatter declares a name, a description, the model it runs on, and its tool restrictions. The description is what Claude Code reads when it decides which agent to dispatch, so it is reproduced verbatim below.

Agent names are identifiers, and are set in mono throughout.

At a glance

Group	Agents
Coordinate	orchestrator
Discover	scout, explore, librarian, vision
Plan and challenge	planner, validator, critic, advisor
Build	builder, builder-standard, builder-simple, test-writer
Verify	qa-guard, reviewer
Document	doc-researcher, doc-writer

Coordinate

orchestrator

Full-lifecycle development coordinator. Manages discovery, analysis, planning, execution, review, and delivery by dispatching specialized agents. Guides the user through approval gates between phases. Use as default agent for any non-trivial task.

Model claude-opus-5 · Denied tools Edit · agents/orchestrator.md

Discover

scout

Pre-planning consultant. Analyzes requests to identify hidden intentions, ambiguities, and AI failure points before planning begins.

Model claude-opus-5 · Denied tools Write, Edit · agents/scout.md

explore

Codebase search specialist. Finds files, code patterns, and relationships. Fire multiple in parallel for broad searches.

Model claude-haiku-4-5 · Denied tools Write, Edit · agents/explore.md

librarian

External documentation and OSS code search specialist. Finds official docs, implementation examples, and best practices using web search and GitHub.

Model claude-sonnet-5 · Denied tools Write, Edit · agents/librarian.md

vision

Interprets media files (PDFs, images, diagrams, screenshots) that require visual analysis beyond what the Read tool extracts as plain text. Returns only the extracted information, not the raw file.

Model claude-sonnet-5 · Allowed tools Read · agents/vision.md

Plan and challenge

planner

Strategic planning consultant. Interviews users, gathers requirements, and creates detailed work plans. Read-only except for .sisyphus/ markdown files.

Model claude-opus-5 · Denied tools Edit · agents/planner.md

validator

Work plan reviewer. Verifies plans are executable with valid references. Blocker-finder, not perfectionist.

Model claude-opus-5 · Denied tools Write, Edit · agents/validator.md

critic

Devil's-advocate reviewer. Challenges a plan's approach and assumptions in a single bounded pass — blind spots, shaky premises, overlooked alternatives, and PII/legal exposure — then returns ranked challenges and a verdict. Read-only advisor, invoked at the end of planning for high-stakes work or on demand. Distinct from scout (pre-plan risk triage), validator (executability), advisor (design direction), and reviewer (built-code audit).

Model claude-opus-5 · Denied tools Write, Edit · agents/critic.md

advisor

Read-only architecture advisor. Deep reasoning for debugging, design decisions, and multi-system tradeoffs.

Model claude-opus-5 · Denied tools Write, Edit · agents/advisor.md

Build

builder

Implementation specialist. Executes one scoped task from a plan — writes the code, proves it works, reports honestly. Complex tier — design judgment: architectural decisions, cross-system impact, or genuine ambiguity. Same contract as the cheaper tiers, running on Opus. Distinct from planner (decides what to build), advisor (decides how it should be shaped), and reviewer (audits it after the fact).

Model claude-opus-5 · agents/builder.md

builder-standard

Implementation specialist — standard tier. Tasks needing some judgment: one or two local decisions, or an existing pattern that needs adapting rather than copying. Same contract as builder; runs on Sonnet. Use when the plan classifies the task as standard. Distinct from planner (decides what to build), advisor (decides how it should be shaped), and reviewer (audits it after the fact).

Model claude-sonnet-5 · agents/builder-standard.md

builder-simple

Implementation specialist — simple tier. Mechanical, unambiguous tasks where the pattern to copy is already named and there is no decision to make. Same contract as builder; runs on Haiku for cost efficiency. Use when the plan classifies the task as simple. Distinct from planner (decides what to build), advisor (decides how it should be shaped), and reviewer (audits it after the fact).

Model claude-haiku-4-5 · agents/builder-simple.md

test-writer

Test authorship specialist. Writes and extends tests for implemented code — verifies the intended interface, not the current output. Hard file boundary: may not touch implementation files under any circumstances. Distinct from builder (writes production code), reviewer (audits already-built code), and qa-guard (makes CI checks pass mechanically).

Model claude-opus-5 · agents/test-writer.md

Verify

qa-guard

CI gate specialist. Discovers the project's CI checks from config files, runs them, fixes mechanical failures (formatting, linting, type annotations, test setup), and iterates until all checks pass or a real blocker is found. Hard file boundary: may never edit the files that define the checks. Distinct from builder (writes production code), test-writer (writes tests), and reviewer (audits already-built code for quality issues).

Model claude-sonnet-5 · agents/qa-guard.md

reviewer

QA engineer. Audits implemented code or features for bugs, regressions, security flaws, and quality issues, then files a dated, severity-ranked report. Works on code whether pre-delivery (in a worktree or PR) or already landed. Read-only against the code under audit — writes only its report file. Distinct from validator (reviews plans for executability before work begins) and advisor (advises on architecture/design).

Model claude-opus-5 · Denied tools Edit, NotebookEdit · agents/reviewer.md

Document

doc-researcher

Documentation landscape specialist. Reads existing project docs and returns a structured map of coverage, gaps, and update targets — given a description of what just changed. Produces findings for doc-writer; does not write or modify any file. Distinct from explore (reads source code), librarian (reads external docs), and doc-writer (writes documentation).

Model claude-sonnet-5 · Denied tools Write, Edit · agents/doc-researcher.md

doc-writer

Documentation author. Consumes doc-researcher findings and a description of what changed, then writes or updates documentation files using the project's existing vocabulary and structure. Hard file boundary: may not touch implementation files. Distinct from doc-researcher (maps the landscape), builder (writes production code), and reviewer (audits code quality).

Model claude-sonnet-5 · agents/doc-writer.md