Icu Add Activity Message

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

Annotations already declare readOnlyHint=false, idempotentHint=false, and destructiveHint=false, so the write/non-idempotent/non-destructive profile is covered structurally. The description adds value beyond that by noting attribution to the authenticated user and reinforcing the singular-WRITE semantics that the annotations only imply. It doesn't mention the return payload, but an output schema exists, so that is acceptable.

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 operation and its singular/WRITE semantics, then the when-to-use trigger, then the read alternative. Every sentence carries distinct information; no filler.

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?

Annotations, 100% schema coverage, and an output schema mean most structured burden is covered, and the description fills the purpose, trigger, and read/write routing gaps. It could go one step further by distinguishing the related update/delete message siblings (icu_update_activity_message, icu_delete_activity_message), which are also singular write operations.

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 only two parameters (activity_id, content), both documented in the schema. The description implies what goes into content ("note or comment") but adds no format, length, or validation detail beyond the schema. Baseline 3 applies when the schema carries the semantics.

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 ("POST a new note or comment on a specific activity") and explicitly labels the singular form as the WRITE operation. It distinguishes itself from the read sibling icu_get_activity_messages (plural) by name, so an agent can separate the two without opening either 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 an explicit "use when" trigger with three concrete user-utterance examples ("add a note to this ride that I felt strong", "comment on yesterday's run", "leave a training note"). It also names the alternative for the opposite case: "To READ existing notes use icu_get_activity_messages (plural)."

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