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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so the safety profile is covered. The description adds real value on top: it signals no cost is incurred ('spending responses'), no external fetching occurs ('visiting websites' — consistent with openWorldHint=false), and only already-saved data is returned.

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 tight sentences with purpose front-loaded and zero filler. The final clause is dense ('spending responses' is slightly cryptic) but every sentence carries information, so it is appropriately sized.

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 shape need not be described, and annotations cover the safety profile. However, the required messageId and the studyId/studyName parameters are unexplained, leaving the agent without enough to know how to key the call correctly.

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% for all four parameters, so the description carries the full burden, and it only explains one: assetKey ('selects its saved upload path or normalized URL'). The required messageId, plus studyId and studyName, are left completely undocumented in both schema and description, which is a significant gap for the sole required parameter.

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 ('Reads saved heatmaps of an assigned question asset'), which is a distinct action from the sibling start_study_heatmap. The phrase 'without starting analysis' effectively separates it from that sibling, though it never names the alternative explicitly, which keeps it just short of a 5.

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 clause 'without starting analysis, spending responses or visiting websites' tells the agent when this tool is the right choice versus triggering a fresh analysis (start_study_heatmap). There is no explicit when-not statement or named alternative, so it stops at clear-context guidance rather than full routing.

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