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

Annotations already declare readOnlyHint=false, destructiveHint=false, and idempotentHint=true. The description adds meaningful behavior: immediate save with url/base64, return of mediaId, 15-minute upload URL expiry, and the curl PUT follow-up with response field media.mediaId.

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-loads the core action and return value, then efficiently describes each mode. The curl example is compact and directly useful, with no filler content.

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, but the description supplies the key return value (mediaId or media.mediaId) and explains all invocation paths. An agent has enough information to call the tool correctly across url, base64, and local-file workflows.

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%, so the baseline is 3. The description adds important mode-selection semantics: providing url or base64 saves immediately, while omitting both returns an upload URL. It also clarifies that url must be https, though the optional name parameter is not discussed.

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: saves a capture in the account and returns mediaId. The three invocation modes are clearly within scope, and no sibling tool overlaps with media upload.

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?

Explicitly explains when to pass url, when to pass base64, and that no arguments returns a 15-minute upload URL for local files. It does not compare against sibling tools, but those are tour/step operations, so alternative guidance is largely unnecessary.

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