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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint, so the description only needs to add behavioral nuance. It adds the requirement of an exact ID and the warning not to pass a display name. It does not detail error behavior or return format, but the safety profile is fully covered by annotations.

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 tight sentences with no filler. The key constraint (exact ID, not display name) is front-loaded, and every sentence earns its place.

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 simple read-only get-by-id operation, the description, schema, and annotations together provide enough to call it correctly. It does not describe the return value, but that is typically inferred for a 'get' operation and the absence of an output schema does not create ambiguity.

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%, so the schema already documents both parameters. The description reinforces the calendar_id semantics (exact ID, obtain via list, never display name) but adds little beyond the schema's own text. This matches the baseline 3 for high coverage.

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 states a specific verb and resource ('Get one calendar') and immediately scopes it to 'the exact ID returned by calendar_list_calendars', which distinguishes it from the listing sibling. It also explicitly warns against passing a display name, preventing misuse.

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?

The description gives clear context: use the exact ID from calendar_list_calendars, and explicitly forbids passing a calendar display name. It does not name alternative tools or explain when to prefer this over other calendar operations, but the prerequisite and constraint are unambiguous.

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