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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, closed-world), so the bar is lower, yet the description still adds the auth model (account key required on the request), the share-token limitation, result ordering (newest first), per-item content (access owner or reader), and cost ('Free'). These are behavioral traits the structured fields do not convey.

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 sentences, front-loaded with what is listed and in what order, then routing guidance, then the auth/cost constraints. Every clause carries information; there is no filler or restated title.

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 parameterless list tool with an output schema and full annotation coverage, the description supplies everything an agent needs to decide to call it: auth prerequisites, access-scope semantics, ordering, and the share-token exclusion. Return-value structure is delegated appropriately to the 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?

The tool takes zero parameters and schema coverage is 100%, so there is nothing for the description to disambiguate; the baseline for parameterless tools applies. No misleading or missing parameter guidance is present.

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 ('Lists the saved snapshots') and narrows scope precisely: snapshots the account behind the request's key owns or was granted access to, newest first. It also distinguishes itself from get_snapshot and compare_snapshot by naming them as the downstream consumers of the snapshotId it returns.

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?

Explicit when-to-use: 'Call it to find a snapshotId for get_snapshot or compare_snapshot.' Explicit when-not/alternative: 'a share token names one snapshot and cannot list', which tells the agent this tool is the wrong entry point for share-token-based access.

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