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

Annotations only declare the generic non-readonly/non-idempotent profile; the description adds the real behavior: URLs are PUT-only (not an upload route on their own, or the version stays stuck in 'uploading'), 15-minute URL validity, the required finalize_upload step, PPTX→page-image conversion with possible font substitution, and that quota errors carry recovery guidance.

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?

Front-loaded with the core action, then routing rules, caveats, mechanics. Dense and mostly waste-free, though the trailing keyword block is boilerplate rather than information.

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 non-idempotent mutation tool with no output schema, the description covers the full lifecycle (create version → get PUT URLs → upload bytes → finalize_upload), timing constraints, conversion side effects, and error recovery. Nothing an agent needs to call it correctly is missing.

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 only 33%, and the description mainly restates the required file triple ('relative path, byte size and SHA-256') — though 'relative' does add a nuance beyond the schema. It says nothing about the required proposal_id or the optional note/mime fields, so it only partially compensates for the coverage gap.

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 ('Open a direct upload session') plus its mechanism ('a presigned URL per file'), and explicitly distinguishes itself from the sibling routes publish_file and create_upload_link. An agent can tell what it does and what it is not without opening the schema.

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?

Gives an explicit decision tree: terminal ⇒ SPACE CLI (create_cli_token first); no terminal + text files ≤2MB ⇒ publish_file; otherwise/unsure ⇒ create_upload_link, plus a hard exclusion ('without a terminal do not open one'). This is exactly the when/when-not/alternatives guidance the dimension asks for.

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