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

Annotations already establish read-only, idempotent, non-destructive behavior, and the description adds genuinely new traits: bounded output ('top five findings'), graceful degradation ('missing, restricted or not-yet-ready sections are marked unavailable'), and a defined edge-case response for ambiguous block selection. It stops short of describing pagination or ordering, but the edge-case disclosure is substantive.

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 dense sentences with no filler; the payload enumeration is front-loaded and the negative constraint is last. It is compact for the amount of information conveyed, though 'strengths and navigation metrics' reads as a list dump rather than a prioritized statement.

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?

Because an output schema exists, return values needn't be spelled out, and annotations carry the safety profile, so the description's remaining job is scope plus edge cases — both covered. The only real gap is resolving the required testId versus the optional scoping IDs and the boundary against get_test_report.

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 0% across three parameters, so the description carries the burden, and it only partially discharges it: it names runId and blockId as optional scoping inputs and hints that blockId may resolve ambiguously, but it says nothing about the required testId, nor about ID formats or why blockId takes an arbitrary string while the other two are 24-char hex.

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?

Starts with a specific verb ('Read') and a concrete resource ('usability-results overview'), then enumerates the payload (metadata, top five findings, optimization/satisfaction scores, strengths, navigation metrics). It differentiates itself from write siblings via 'Does not launch or modify tests,' but never contrasts itself with the near-neighbor get_test_report or get_test, so the reader must infer that this is the lighter-weight aggregate view.

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?

The description explains how runId and blockId scope results, which implies usage, and the closing sentence excludes launching/modifying. However, it never states when an agent should pick this overview instead of the many sibling result tools (get_test_report, get_optimization_score, get_satisfaction_score, get_test_progress), so selection guidance is only implied.

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