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

Annotations already declare readOnly, idempotent, non-destructive, and open-world, but the description adds important behavioral context beyond them: the return shape, the 250-item page cap, the fact that results are NOT auto-paged, and the exact recovery pattern via paging.hasMore and offset=paging.nextOffset. This is exactly the kind of operational detail an agent needs before concluding a run is missing.

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 core purpose, then follows with return shape, pagination caveat, and filtering advice. Every sentence adds distinct operational value, with no redundant or filler text.

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?

For a list tool with five parameters, rich annotations, and no output schema, the description covers purpose, return shape, pagination behavior, and filtering guidance. An agent has enough information to call it correctly and interpret results without needing an output schema.

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%, which sets a baseline of 3, but the description adds meaning beyond the schema by tying offset to paging.nextOffset and explaining the practical use of milestoneId and createdAfter for release- or window-based filtering. It does not explain limit semantics beyond what the schema already states.

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 and resource ('List TestRail runs') and scopes it to a project with ordering ('newest first'). The resource is clearly distinct from sibling tools like testrail_list_tests_for_run, which lists tests within a run rather than runs themselves.

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 explicit usage guidance for pagination and filtering: check paging.hasMore and re-call with offset=paging.nextOffset, and use milestoneId or createdAfter to avoid paging through history. It does not name when to prefer this over a sibling tool or state when not to use it, so it falls short of full 5-level routing guidance.

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