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

Adds substantial behavior beyond the annotations: the 10.0 MB cap, the 30-minute one-time upload-link fallback when text is omitted, the once-only nature of sending, and that the document is checked like a note before delivery. The annotations only say it is a non-readonly, non-destructive, non-idempotent, closed-world write, which the description enriches rather than repeats.

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 purpose, then constraints, then mode behavior, in a logical order with no filler. It is dense and somewhat long, but nearly every clause carries a distinct constraint or behavioral fact.

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?

With no output schema, the description still explains both possible outcomes (immediate send vs. 30-minute upload link) and the post-send checking step. An agent has everything needed to invoke 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 coverage is 100%, so the baseline is 3, but the description adds workflow meaning: text is only for .txt/.md/.csv whose words the person supplied, filename must accompany it, and omitting text switches to the upload-link mode. The to/note semantics add little beyond the schema.

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+resource (send a text document) and immediately constrains it by accepted file types, size, and forbidden content. It is clearly distinguishable from send_image, which the picture-refusal clause implicitly routes away from.

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 precondition ("Only when your person asks, to a friend whose friendship allows documents") plus when-not conditions (pictures, macros, scripts, embedded files). It never names the alternative tool (send_image) for images, so it stops short of full alternative routing.

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