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

Annotations already declare a non-read-only, non-destructive, open-world write. The description adds two useful facts beyond them: the app must be 'connected', and the change applies to 'new bookings' only. It does not state what happens to the previously set default or whether permissions/scopes are required.

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 no filler; the scope qualifier 'for new bookings' is placed where it matters.

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 one-parameter setter with full schema coverage and no output schema, the description is nearly complete. The only meaningful omission is what becomes of the prior default, though the definite article 'the default' implies replacement.

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% and the 'app' parameter already documents the id source and examples (zoom, google-meet, ...). The description adds no parameter-level information, so the baseline 3 applies.

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?

Specific verb+resource: 'Make a connected video-conferencing app the default for new bookings.' An agent knows exactly what this changes. It does not differentiate from siblings such as get_default_conferencing or list_conferencing_apps, which would have justified a 5.

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 only implied: 'connected' hints that the app must already be connected, and 'for new bookings' scopes the effect, but there is no explicit when-to-use, when-not, or reference to alternatives. The routing to list_conferencing_apps appears only in the schema's parameter description, not the tool description.

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