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

With no annotations, the description carries the full burden and does so well: it discloses the consent requirement, that nothing is stored server-side, where the event actually lands (their .ics or CalDAV), that the receipt names the authorizing grant, and the deletion semantics. This is rich behavioral context beyond the schema.

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 the core action and the [KEEP · internal] tag, then flows into prerequisites and behavior. Some sentences are dense and the arrow-flow is compact, but essentially 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 mutation tool with no annotations and no output schema, the description covers consent, storage, destination, and deletion. The main gap is parameter documentation, which is missing entirely given 0% schema coverage.

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 0% and the description does not explain any of the 6 parameters. Names like grantor_pubkey and agent_fp are cryptically left to the caller; start_iso/end_iso format is not specified. The description doesn't compensate for the total lack of schema documentation.

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 (Create) and resource (ONE event in a human's calendar), and explicitly scopes it as 'the pilot on-behalf write, and the only one.' An agent can distinguish this from anything in the large sibling list without opening the schema.

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?

Provides the critical prerequisite (a LIVE consent grant) and even outlines the acquisition flow (GET /consent/signable → sign locally → POST /consent), plus what happens without it ('refuses and teaches the way in'). No explicit when-not-to-use alternatives are named, but the required precondition is unusually clear.

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