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

Annotations already declare readOnlyHint=false and destructiveHint=true, so the agent knows this is a mutating operation. The description adds valuable context beyond the annotations: the update happens 'in place' and does not create a new timeline item. This is a meaningful behavioral disclosure because it tells the agent the operation won't have the side effect of adding a timeline entry. It doesn't disclose reversibility or permission requirements, but the annotations carry the destructive hint, so the description adds sufficient context.

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?

A single sentence that front-loads the action ('Update a note's body or visibility') and then adds the critical behavioral qualifier ('in place, without a new timeline item'). Every word earns its place; there is no filler or repetition of schema details.

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 update tool with four parameters and no output schema, the description is nearly complete. It identifies the resource, the updatable fields, and the key side-effect distinction. The only minor gap is that it doesn't mention the 'include' parameter's behavior or any prerequisites (e.g., the note must exist), but the schema covers the parameter descriptions and the operation is straightforward. The annotations cover the destructive nature, so nothing critical is missing.

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 75%, so the schema already documents three of the four parameters (body, include, visibility). The description adds the semantic distinction that body and visibility are the updatable fields, which maps to the schema. The 'id' parameter is required but has no description in the schema, and the description doesn't explain it either, though it's self-evident as the note identifier. The description doesn't add much beyond the schema, but the schema covers most parameters, so baseline 3 is appropriate.

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 states a specific verb ('Update'), a specific resource ('a note's body or visibility'), and a key behavioral distinction ('in place, without a new timeline item'). This clearly differentiates it from hires_create_note and hires_delete_note, and even from hires_update_message, since it explicitly names the note resource and the no-timeline-item behavior.

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?

The phrase 'in place, without a new timeline item' gives clear context for when to use this tool: when you want to modify an existing note without creating a new timeline entry. It implies the alternative (hires_create_note) creates a new timeline item, but it doesn't explicitly name the alternative or state when not to use it. The sibling list contains hires_create_note, so the contrast is implied but not explicit.

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