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

The 'WRITE:' prefix and 'replace the text' wording make concrete why destructiveHint=true — the prior note text is overwritten — which is real context beyond the bare annotation flags. It also discloses the underlying PATCH endpoint. It stops short of stating error behavior for a missing note id or permission requirements.

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, operation type front-loaded in a scannable 'WRITE:' tag, followed by the endpoint. No filler, and the most decision-relevant detail (replace vs create) comes first.

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 3-required-parameter mutation with no output schema, the definition covers what is mutated, where the ids come from, and the API path. What is missing is failure-mode behavior (nonexistent note id), whether the note's timestamp changes, and any auth scoping — minor but real gaps.

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?

With 100% schema description coverage, the schema already documents all three parameters including the `notes[].id` provenance for note_id. The description only restates that mapping and maps names to path segments (callId, noteId), adding marginal semantics — the baseline 3 applies.

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 pairs the specific verb 'replace' with the resource 'the text of an existing note on a call record', and the 'existing note' qualifier separates it from rinkel_add_call_note and rinkel_delete_call_note. An agent can pick this tool over its note-related siblings without opening any 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?

Usage is implied rather than stated: 'existing note' rules out creation, and the pointer to `notes[].id` tells the agent where to find the required id. However, no alternative is named explicitly (e.g. use rinkel_add_call_note to create, rinkel_delete_call_note to remove), so routing still requires inference from the sibling list.

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