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

Annotations already declare readOnly/idempotent/non-destructive, yet the description adds materially new behavior: it is FREE, it accepts no arguments, it returns metadata only (no persona text, no skill instructions), and it never raises a protocol error but instead returns {"error": ...} with remediation guidance. That error contract plus the safe-retry assurance is exactly the context annotations cannot carry.

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?

Front-loaded and well organized: purpose, cost, argument contract, return shape, routing guidance, then error behavior. It loses a point because 'Takes no arguments' and the inline return-shape example partly duplicate the empty schema and the existing output schema.

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?

An output schema exists, yet the description still pins down the important things an agent needs: cost, that results are metadata-only, how slugs feed other tools, and the non-throwing error contract. Nothing required to call it correctly is missing.

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?

Zero parameters, so the baseline is 4, and the description confirms 'Takes no arguments.' It also explains how to consume the returned slug values in sibling tools, which is useful but borders on output documentation rather than parameter semantics.

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?

Opens with a specific verb and resource plus scope: 'List the 7 outbound products with their included skills.' It immediately differentiates from siblings by naming what it is not (search_catalog, get_free_skill) and by pointing to get_free_skill/get_full_product/get_full_skill for follow-up calls.

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 trigger ('Use when the caller wants to see what this server covers') plus two explicit exclusions with the correct alternative named for each: keyword search belongs to search_catalog, actionable instructions belong to get_free_skill. Nothing is left to inference.

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