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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so the safety profile is covered. The description adds the transport endpoint (POST /v1/ics-sanitizer) and the three processing behaviors, but says nothing about output shape, partial-failure behavior on unparseable input, or whether normalization is lossy.

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?

One sentence plus a parenthetical endpoint, front-loaded with the verb list. It is efficient and easy to scan; the only waste is restating the tool title as a prefix.

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 single-parameter, annotation-covered read tool this is close to sufficient, but with no output schema the description leaves the return value (repaired feed, JSON wrapper, parse errors) entirely unspecified. An agent cannot predict what it will receive.

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?

There is a single required parameter with 100% schema coverage and an inline example of the expected iCalendar string. The description confirms the input is a feed but adds no encoding, size, or multiline-escaping detail beyond the schema, so the schema carries the parameter burden.

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?

Names a specific resource (ICS/iCalendar feeds) and concrete operations: repair, normalize Windows timezones to IANA, parse VEVENTs. That is far more informative than the name alone, though the leading title phrase duplicates the tool title rather than adding differentiation.

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: an agent can infer this is the tool for broken or Windows-timezoned .ics feeds. It never states when to use it versus not, no prerequisites, and no mention of what constitutes a 'broken' feed versus a valid one that should be passed through unchanged.

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