Send a file

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

Annotations already declare the safety profile (readOnlyHint=false, idempotentHint=false, openWorldHint=true, destructiveHint=false), so the bar is lower. The description adds only that the source file is local, and says nothing about auth requirements, upload/size limits, or failure behavior when the path is invalid — modest added value over the structured fields.

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?

A single front-loaded sentence with zero filler; the verb and resource lead. It is arguably too terse for the tool's role next to an ambiguous 'send' sibling, but nothing in it is wasted.

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 low-complexity, 3-parameter tool with full schema coverage, annotations covering the safety profile, and no output schema, the description contains enough to invoke it correctly. Gaps are minor: no mention of upload constraints or error behavior for a bad path.

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% ('Absolute path to the file to send', '@username, numeric id, or me', 'Caption to attach'), so the schema carries full parameter meaning. The description only restates that the caption is optional, adding nothing beyond the schema — baseline 3 is correct here.

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 gives a specific verb and resource ('Send a local file'), names the destination ('to a chat'), and notes the optional caption. 'Local file' usefully distinguishes it from the sibling download_media (which moves media the other way), but it does not clarify how it differs from the plain 'send' sibling, which is a real ambiguity for an agent choosing between the two.

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?

Usage is implied by the purpose — an agent reading 'send a local file' knows this is the tool for uploading a file to a chat. However, no when-to-use condition, exclusion, or alternative is stated, and the overlap with the sibling 'send' is left unresolved, so the agent must infer the routing rule.

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