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

Adds substantial context beyond the annotations: 24h expiry, the PUT-with-declared-content-type mechanic, a concrete curl example, the note that the binary stays out of the conversation, the 25 MB cap, the MIME whitelist, and the 'mints no model data, so it stays available to read-only keys' authorization note. This is exactly the behavioral disclosure the annotations alone would 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?

Dense yet well-ordered: the core action and return values come first, followed by the invocation mechanic, then limits and the availability note. No sentence is filler.

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?

There is no output schema, so the description carries the return contract and does so completely (file_id, signed_url, expires_at). Limits, MIME whitelist, and the read-only-key accessibility round out what an agent needs to call it 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 100%, so the three parameters are already documented in the schema. The description restates the 25 MB limit and MIME whitelist but adds no new per-parameter syntax or format guidance, 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 and resource: 'Issues a 24h signed Storage URL for an Excel/CSV file.' It clearly identifies the tool as an upload-URL minter, which is readily distinguishable from file-related siblings like layerz_parse_file and layerz_export.

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?

Implies the intended workflow by noting 'file_id is the identifier the file-consuming tools take' and that the signed_url accepts a PUT, which tells an agent how to chain it with downstream tools. It stops short of explicitly naming those alternatives or stating when-not to use it, so it does not reach a 5.

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