Catalog (freely callable)

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

Annotations already declare readOnly/idempotent/non-destructive/closed-world, so the bar is lower, yet the description adds real behavior: the upstream list is fetched once and sliced locally, truncated means upstream withheld data, and null price_segment means unassigned rather than 'economy'. It is a meaningful addition beyond the annotation set.

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 with the core purpose and then the return/newline-separated operational rules; each sentence carries information. Describing return fields is somewhat redundant given an output schema exists, which keeps it from a 5.

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?

Covers purpose, paging protocol, truncation recovery, and null semantics for a 3-param read tool, and the output schema handles the return shape. An agent has everything needed to call it correctly on the first attempt.

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?

Schema description coverage is 100%, so limit, offset and price_segments are already fully documented in the schema (ranges, defaults, known slugs, an MCP-side bound of 20). The description restates the slicing/paging behavior but adds little parameter syntax or format detail beyond it, so the baseline 3 is appropriate.

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?

States a specific verb+resource ('List tire brands in the TiresVote catalog'), clearly distinguishable from siblings like tires_list_brand_tires or tires_list_sizes. It also clarifies the scope of the returned entities, so an agent can route to it without opening the schema.

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?

Gives concrete operating guidance: page with limit/offset, follow next_offset while has_more, and narrow price_segments on truncated. It also notes the slug is the identifier other catalog tools consume, which is genuine cross-tool routing info. It stops short of naming explicit alternatives or exclusions versus sibling list tools.

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