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Agent Review Skill

Critically review a Stencila agent and suggest improvements. Use when asked to review, audit, critique, evaluate, or improve an agent directory or AGENT.md file. Covers frontmatter validation, system instruction quality, configuration correctness, and adherence to the Agent schema.

Keywords: agent · review · audit · critique · evaluate · improve · AGENT.md

Usage

To use this skill, add agent-review to the allowed-skills list in your agent's AGENT.md. You can also ask #agent-creator to build an agent that uses it.

Configuration

PropertyValue
Allowed toolsread_file, glob, grep, shell, ask_user

Instructions

Overview

Review an existing Stencila agent for quality, correctness, and completeness. Produce a structured report with specific, actionable suggestions. The review covers frontmatter fields, system instruction quality, configuration correctness, security posture, and adherence to the agent schema defined in schema/Agent.yaml.

Steps

  1. Identify the agent to review from the user's request — accept an agent name, a directory path, or an AGENT.md file path

  2. Resolve the agent file: if given a name, look for .stencila/agents/<name>/AGENT.md walking up from the current directory; also check ~/.config/stencila/agents/<name>/AGENT.md for user-level agents. If given a path, use it directly

  3. Read the full AGENT.md file and any supporting files in the agent directory (check for scripts/, references/, and assets/ subdirectories)

  4. Read schema/Agent.yaml to verify the checklist covers current agent schema fields and to identify any unknown frontmatter properties

  5. Evaluate the agent against each criterion in the Review Checklist below

  6. Produce a structured review report with a summary, per-criterion findings, and a prioritized list of suggestions

  7. If the user asks you to apply improvements, make the changes and validate the result with stencila agents validate <agent-name>

Review Checklist

Frontmatter

  • name: present, matches directory name, valid kebab-case (^[a-z0-9]([a-z0-9-]{0,62}[a-z0-9])?$), follows the thing-role naming convention (e.g., code-reviewer, data-analyst)

  • description: present, not empty, not a placeholder (TODO, <placeholder>), recommended to be concise (under ~1,024 characters), specific enough to convey the agent's purpose

Optional Fields

Check each present field for validity:

  • model: do not hard-code a model unless the user explicitly requires one; flag hard-coded models as a warning since they reduce portability

  • provider: same as model — omit unless explicitly needed; flag hard-coded providers as a warning

  • model-size: if present, check that it is being used coherently as a broad model-tier preference (for example small, medium, large), and that it matches the agent's stated role and task complexity. Treat it as a Stencila cross-provider classification rather than an exact provider guarantee

  • reasoning-effort: typically low, medium, or high if present; custom provider-specific values are also valid

  • trust-level: must be low, medium, or high if present; check that it matches the agent's intended use (e.g., a read-only reviewer should not have high trust)

  • allowed-tools: check that listed tools are valid Stencila tool names (read_file, write_file, edit_file, grep, glob, shell, web_fetch, use_skill, spawn_agent, send_input, wait, close_agent, ask_user, mcp_codemode); flag unknown tool names

  • allowed-skills: if present, check that listed skill names are valid kebab-case. Skills that do not yet have a corresponding SKILL.md are valid forward references (top-down design) — note them as outstanding dependencies rather than flagging them as errors

  • allowed-domains / disallowed-domains: if present, check format (exact hosts or *.example.com wildcards)

  • max-turns: non-negative integer if present

  • max-tool-rounds: positive integer if present

  • tool-timeout: positive integer (seconds) if present

  • max-subagent-depth: non-negative integer if present

  • enable-mcp / enable-mcp-codemode: boolean if present

  • allowed-mcp-servers: list of server ID strings if present

  • history-thinking-replay: must be none or full if present

  • truncation-preset: must be strict, balanced, or verbose if present

  • compaction-trigger-percent: unsigned integer (0–100) if present

  • compatibility: under 500 characters if present

  • unknown fields: flag any frontmatter fields not defined in schema/Agent.yaml (or inherited from CreativeWork) as warnings — they may be typos or unsupported properties that will be silently ignored

Note: Agent extends CreativeWork in the schema, so agents may have additional valid fields such as license. Verify against the schema before flagging inherited properties as unknown.

If both allowed-skills and allowed-tools are present, check tool coverage across skills: the agent's allowed-tools should include all tools required by the allowed skills. use_skill is optional for exactly one allowed skill because that skill is preloaded automatically, but should be present when the agent may need to invoke skills dynamically or choose among multiple skills.

Discovery and Delegation Metadata

  • keywords: if present, check that keywords are relevant, not redundant with the description, and include likely user intent words, artifact types, and domain terms. Flag generic or overly broad keywords. If absent, recommend adding keywords to improve discoverability

  • when-to-use / when-not-to-use: if present, check that entries are specific, actionable, and complementary to the description rather than duplicating it. Flag vague signals like "when appropriate" or "when needed". If absent, recommend adding them to improve manager delegation accuracy

  • Coherence check: verify that description, keywords, and when-to-use/when-not-to-use work together — they should be complementary, not redundant. Flag cases where the same text appears verbatim in multiple fields

System Instructions and Body

  • A missing body is valid — a frontmatter-only AGENT.md is a legitimate configuration-only agent. However, a body that exists but contains only empty sections or placeholder content should be flagged

  • If allowed-skills contains exactly one skill, recognize that Stencila automatically preloads that skill's full instructions into the system prompt. In this case, a short body that acts as a preamble or identity-setting introduction is sufficient and should not be criticized as too sparse merely for brevity

  • If present, instructions are clear, imperative, and unambiguous

  • Instructions align with the agent's described purpose — a code reviewer's instructions should not describe code generation

  • No contradictions between frontmatter configuration and body instructions (e.g., body says "modify files" but allowed-tools excludes write_file and edit_file)

  • No placeholder content (TODO, <placeholder>, or empty sections)

Security

  • Tool scope: agent only has access to tools it needs; flag overly broad tool access for specialized agents (e.g., a documentation agent with shell access)

  • Trust level: appropriate for the agent's role; flag high trust on agents that do not need it

  • Domain restrictions: if the agent uses web_fetch, consider whether domain restrictions are appropriate

  • MCP access: if MCP is enabled, check whether allowed-mcp-servers restricts access to only needed servers

Consistency

  • Frontmatter property names use kebab-case (not camelCase or snake_case)

  • Formatting is consistent (heading levels, list styles, code block languages)

  • Naming follows thing-role convention

  • Configuration choices are internally consistent (e.g., max-turns: 5 with reasoning-effort: high suggests the agent expects complex tasks but has limited turns)

  • model-size and reasoning-effort are used coherently: model-size should reflect the desired cost/latency/capability tier, while reasoning-effort should reflect how much the selected model should deliberate. Flag cases where a very simple agent uses an unnecessarily large model tier without justification, or where a demanding analysis/review agent likely needs a larger tier than configured

Report Format

Structure the review as follows:

Summary

One to three sentences giving an overall assessment and the most important finding.

Findings

For each checklist area, report one of:

  • ✅ Pass — criterion fully met

  • ⚠️ Warning — minor issue or room for improvement

  • ❌ Fail — significant problem that should be fixed

Include a brief explanation for warnings and failures.

Suggestions

A numbered list of specific, actionable improvements ordered by priority (most impactful first). Each suggestion should explain what to change and why.

Use heading level 3 (###) for each section in your output.

Examples

Input: "Review the code-reviewer agent"

Process:

  1. Resolve to .stencila/agents/code-reviewer/AGENT.md

  2. Read the file and check for supporting files in subdirectories (scripts/, references/, assets/)

  3. Read schema/Agent.yaml to verify field validity

  4. Evaluate frontmatter: name is code-reviewer, matches directory, valid kebab-case, follows thing-role convention; description is specific

  5. Check optional fields: model-size: medium and reasoning-effort: high are a sensible combination for a read-only reviewer; allowed-tools lists read_file, grep, glob, shell — appropriate for that role

  6. Evaluate body: instructions say "do not modify files" — consistent with read-only tools

  7. Check security: no write_file or edit_file — good least privilege

  8. Run stencila agents validate code-reviewer

  9. Produce the report

Output (use ### headings in the report):

Summary

The code-reviewer agent is well-configured with appropriate read-only tool restrictions and clear instructions. One minor improvement is possible.

Findings

AreaStatusNotes
Required fields✅ PassName and description are valid and specific
Optional fields✅ PassAll present fields have valid values
System instructions✅ PassClear, imperative, consistent with tool restrictions
Security✅ PassRead-only tools, appropriate trust level
Consistency⚠️ Warningreasoning-effort is not set; consider high for code review tasks, and consider model-size: medium if the agent should consistently avoid the smallest tier

Suggestions

  1. Add reasoning-effort: high — code review benefits from deeper analysis, and this matches the defaults in the agent-creation skill's configuration guide

  2. Consider model-size: medium — this keeps the agent portable across providers while signaling that review work typically needs more than the smallest, fastest model tier

Input: "Review the code-reviewer agent that delegates to one skill"

Process:

  1. Resolve to .stencila/agents/code-reviewer/AGENT.md

  2. Read the file — frontmatter includes allowed-skills: with exactly one entry, code-review

  3. Note from the agent configuration pattern that a single allowed skill is preloaded into the system prompt automatically

  4. Evaluate the body as a short preamble that frames the agent's identity, rather than expecting the full workflow to be repeated there

  5. Check that the body is not placeholder text and does not contradict the preloaded skill or tool restrictions

  6. Produce the report without flagging the short preamble as too sparse

Output (use ### headings in the report):

Summary

The code-reviewer agent is appropriately concise for a single-skill setup. Its short body works as a preamble, and the substantive workflow is supplied by the preloaded code-review skill.

Findings

AreaStatusNotes
Required fields✅ PassName and description are valid and specific
Optional fields✅ Passallowed-skills has one valid skill name, which indicates a preloaded single-skill configuration
System instructions✅ PassThe body is brief but appropriate because it frames the agent and the detailed instructions come from the preloaded skill
Security✅ PassTool access matches the review-only role
Consistency✅ PassThe configuration and preamble are internally consistent

Suggestions

  1. Optionally expand the preamble by one sentence if you want a stronger agent identity, but do not duplicate the preloaded skill instructions

Input: "Review the quick-helper agent"

Process:

  1. Resolve to .stencila/agents/quick-helper/AGENT.md

  2. Read the file — frontmatter has name: quick-helper, description: Helps with stuff, trust-level: high, allowed-tools: read_file write_file edit_file shell web_fetch spawn_agent; body says "You are a helpful assistant" with a ## TODO section

  3. Read schema/Agent.yaml to check field validity

  4. Evaluate against the checklist

  5. Produce the report

Output (use ### headings in the report):

Summary

The quick-helper agent has significant configuration issues: an overly broad tool set for an unspecified purpose, unnecessarily high trust, a vague description, and placeholder content in the body.

Findings

AreaStatusNotes
Required fields⚠️ WarningDescription "Helps with stuff" is too vague to convey the agent's purpose
Optional fields⚠️ Warningtrust-level: high is set without clear justification
System instructions❌ FailBody contains a ## TODO placeholder section
Security❌ FailAgent has shell, web_fetch, and spawn_agent with trust-level: high but no clear need for these capabilities
Consistency⚠️ WarningName quick-helper does not follow thing-role convention — unclear what domain it covers

Suggestions

  1. Remove placeholder ## TODO section or replace it with actual instructions

  2. Reduce trust-level to medium (or low) unless elevated trust is justified by the agent's purpose

  3. Restrict allowed-tools to only the tools the agent needs — remove shell, web_fetch, and spawn_agent unless required

  4. Rewrite description to specifically convey what the agent does and when to use it

  5. Rename to follow thing-role convention (e.g., general-assistant or a more specific name)

Edge Cases

  • Agent not found: Report the error clearly and suggest checking the name or path. List available agents if possible using stencila agents list or by listing .stencila/agents/ directories.

  • Multiple agents requested: Review each agent separately with its own report section. Ask the user to confirm if reviewing all agents is intended.

  • Frontmatter-only agent (no body): This is valid — do not flag it as a failure. A frontmatter-only AGENT.md is a legitimate configuration-only agent.

  • Single allowed skill with brief body: Do not flag a short one- or two-sentence body as too sparse when allowed-skills contains exactly one skill. Treat it as a preamble, because the skill content is preloaded automatically.

  • Unresolved skill references: If allowed-skills lists skill names that have no corresponding SKILL.md, do not flag them as errors. These are valid forward references from top-down design — note them as outstanding dependencies and evaluate the rest of the agent definition on its own merits. The runtime produces a warning for unresolved skill names, not an error.

  • User-level agent: Check ~/.config/stencila/agents/ if the agent is not found in the workspace.

  • Hard-coded model or provider: Flag as a warning, not a failure. Hard-coding reduces portability but may be intentional.

  • Missing model-size: Do not flag absence as a failure. Recommend it only when the agent would benefit from an explicit cross-provider size preference, such as a small tier for quick, low-stakes tasks or a medium/large tier for heavier review and analysis work.

  • Unknown frontmatter fields: Flag any fields not in the Agent schema as warnings — they may be typos or unsupported properties that will be silently ignored.

  • User asks to fix issues: If the user asks you to apply suggestions, make the changes, then validate with stencila agents validate <agent-name> before reporting completion.

Validation

When applying suggested improvements, validate the agent before reporting completion:

# By agent name
stencila agents validate <agent-name>

# By directory path
stencila agents validate .stencila/agents/<agent-name>

# By AGENT.md path
stencila agents validate .stencila/agents/<agent-name>/AGENT.md

Validation should pass before you report the changes as complete.

Limitations

  • This skill reviews the structure, quality, and configuration of an agent definition. It does not test the agent's runtime behavior or execute it against real inputs.

  • The review checks tool names against known Stencila tools but cannot verify that third-party MCP server IDs are valid.

  • Security assessment is based on configuration analysis, not runtime behavior.

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