Complete media upload

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

Annotations already cover the mutation profile (readOnlyHint=false, destructiveHint=false). The description adds useful behavioral context beyond those annotations: the hard dependency on the preceding PUT request, the fact that it will fail or produce unusable media without that step, and the temporary nature of the returned URL. This is meaningful situational transparency.

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 description is three short, front-loaded sentences: step identity, call precondition, and output usage. There is no filler or redundancy, and the complexity is low. It uses a compact, informative structure rather than burying details; a 5 may be one sentence too lean, but this is already efficient.

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 single-parameter tool with an output schema, the description covers the essential context: the step position, the required precondition, failure scenario, return value, and downstream consumers. It does not detail timeouts, retries, or auth, but those are likely shared across the API and not necessary for an agent to call this tool 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 coverage is 100% and uploadId is well-documented as 'upload_id returned by create_media_upload.' The description adds additional semantic constraint not visible in the schema: the uploadId must correspond to an upload whose bytes were actually PUT to the upload_url. This helps the agent reason about valid values beyond the schema's type and origin.

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?

The description explicitly states the tool's role as 'Step 2 of staging a local file' and describes the return value ('temporary media_url'). It distinguishes itself from sibling tools like create_media_upload (step 1) and upload_video/upload_photos/upload_document by positioning the result as the input to those upload tools, giving it a specific verb-resource pairing.

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 gives an explicit conditional: 'Call it only after the file bytes were actually PUT...' and states the failure consequence if that precondition isn't met ('fails or yields no publishable media'). It also provides the downstream usage by naming the three upload tools to pass the returned media_url to, making the intended workflow unambiguous.

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