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

Annotations declare non-read-only, open-world, non-idempotent. The description adds real context beyond that: the 2 GB cap, that the URL must be https and downloadable by Alto, and the side effect of creating one tracked link per recipient. It does not cover failure modes or whether emails are actually dispatched.

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?

Two sentences, zero waste, with the core purpose front-loaded and the sibling routing rule trailing. Every clause carries 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 6-param creation tool with no output schema, the description covers the key inputs and side effects. Minor gap: it implies but does not state whether recipients are notified/emailed, which matters for a tool whose title says 'send it'.

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 50%; url and recipients are documented, while slug, title, duration, and description are not. The description reinforces url constraints (https, 2 GB) and the per-recipient link semantics, which is useful, but it does not compensate for the undocumented slug/duration/description parameters.

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 (upload a finished video that is already online), the mechanism (URL Alto downloads), and the downstream effect (create it, one tracked link per recipient). It explicitly distinguishes itself from the sibling create_upload for local files.

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?

Names the alternative explicitly (create_upload) and the exact condition that selects it (a file on your machine). The agent knows which of the two upload paths to pick without inspecting either schema.

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