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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so the safety profile is fully covered. The description adds useful context beyond that (participant counts are returned, defaults apply on omission, legacy tests are supported), but it says nothing about pagination behavior despite a limit default of 8.

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?

Three short sentences with the core purpose front-loaded and no filler. Every sentence carries some signal, though the 'documented defaults' phrasing is vague enough to weaken the second sentence.

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, so return values needn't be explained. But for a 5-parameter listing tool with low schema coverage, the description omits pagination/limit semantics and status filtering meaning, leaving gaps an agent needs to call it precisely.

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 only 20%, so the description must carry parameter meaning, and it largely does not. It gestures at block/run targeting and default behavior, but limit, status (enum success/drop-off/any), and testId are left unexplained, and the run/block semantics are asserted more than clarified.

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 navigation paths and participant counts'), which is more informative than a generic list tool. It partially differentiates from siblings by naming list_test_blocks as the ID source, though it does not distinguish itself from other list_* tools like list_dropoff_points or list_insights.

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?

Provides workflow guidance by telling the agent to source IDs from list_test_blocks and that omission uses documented defaults. However, it gives no when-to-use vs when-not guidance or alternatives among the many sibling listing tools, leaving selection largely to inference.

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