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

Annotations already declare readOnlyHint=true, so safety is covered, and the description adds nothing behavioral beyond that — no error behavior (e.g., 404 for an unknown id), no auth/permission notes, no rate-limit context. The endpoint string is the only extra detail and is purely structural.

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 short sentences, front-loaded with the purpose; the second sentence is a compact API reference rather than padding. Nothing is wasted, though the second sentence is of marginal value to an agent.

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 single-resource read with no output schema and fully documented parameters, the description is adequate; return values need not be explained. Only the absence of failure-mode context (unknown id, missing grant) keeps it short of complete.

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%, with both grant_id and calendar_id fully documented in the schema. The description only echoes 'by id', adding no syntax, format, or defaulting details beyond the schema baseline.

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 ('Get a single calendar') and the 'single ... by id' phrasing implicitly contrasts with the sibling nylas_list_calendars. It is clear, though it never names the sibling alternative explicitly.

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?

There is no when-to-use guidance, no statement of prerequisites, and no routing to nylas_list_calendars when the id is unknown. The only context given is the underlying REST endpoint, which is not usage guidance.

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