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

With no annotations, the description carries the transparency burden and does well: it discloses that download_url requires an authenticated GET, that signed_url is conditional on publish/bucket-publisher config, that share_url/public_url use the /d/{share_token} route, and that drive_get is deprecated. It does not explicitly state no side effects or auth scopes, so a strong 4 rather than 5.

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 opening sentence front-loads the core purpose and exclusion, and each subsequent sentence adds a distinct fact about returned URLs or aliases. Slightly dense, but no filler; a high 4.

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 one-parameter read tool with an output schema, the description covers the important nuances: pointer-not-body, conditional signed_url, route distinction from shared-file /s/{slug}, attachment IDs, and the deprecated alias. It does not cover error conditions, but that is a minor gap given the schema and simple input.

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 coverage is 100%: the single file_id is documented as 'Storage object UUID'. The description adds no extra parameter semantics, so the baseline of 3 applies.

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 ('Fetch') and object ('Storage metadata and a download pointer') and explicitly delimits scope with '(not the blob body)', which distinguishes it from blob-fetching siblings like file_get. Also notes the deprecated alias drive_get, further disambiguating.

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 makes clear this is the metadata/pointer accessor, not the body download ('not the blob body'), and signals the deprecated alias 'drive_get'. It lacks an explicit 'when not to use' pointer to file_get or storage_list, so one point off.

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