Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations, the description fully discloses behavior: it is a read-only GET endpoint returning public rules. It mentions no side effects, caching advice, and returns structured data with version and domaines. The REST endpoint and HTTP method are explicitly stated, providing complete transparency.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is front-loaded with the critical usage instruction and then provides detailed return structure and context. While it is slightly long, each sentence adds value. It could be more concise, but it is well-structured and efficient.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given the single optional parameter and no output schema, the description fully completes the picture: it explains the return format ({version, domaines, urls}), content type (public rules), and endpoint (GET /api/v1/agent-playbook). It also clarifies that server-side guardrails are authoritative, adding necessary context.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The schema already describes the only parameter 'domaine' as an optional filter with an enum of values. The description mentions a subset of domains ('securite, documents...') but does not add new meaning beyond the schema. With 100% schema coverage, this meets the baseline expectation.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the tool's purpose: 'FREE versioned playbook of best practices for MCP/API agents.' It specifies when to call it ('WHEN you discover this server — call it FIRST, before anything else') and distinguishes it as a public, read-only guide. This makes the purpose unambiguous and distinct from sibling tools.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

Explicit usage guidance is provided: 'call it FIRST, before anything else, and again if your cached instructions may be stale.' It also clarifies that it contains no tenant data and that server-side guardrails remain authoritative, implying when not to rely on it for proprietary rules. The description leaves no doubt about when to use this tool.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.