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

Annotations already declare readOnlyHint=false and destructiveHint=false, and the "WRITE:" prefix is consistent with that rather than contradicting it. The description adds genuinely non-obvious behavioral context the annotations cannot carry: the note lands in entity history and produces no outbound communication to the contact, which is exactly the risk question an agent would have before calling a write tool.

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?

Three short fragments, zero filler, with the WRITE classification and the core action front-loaded before the side-effect clarification. Every sentence earns its place.

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?

With annotations covering the safety profile and full schema coverage of all seven parameters, the description supplies the missing conceptual layer: multi-entity attachment and the absence of contact notification. The one real gap is that the schema requires only name and content while the description says "one or more" targets, leaving the agent unsure whether an untargeted note is valid or orphaned.

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%, so name, content, the four *_ids arrays and confidential are all documented in the schema, making the baseline 3 appropriate. The description's "one or more people, companies, deals or projects" adds a little framing by grouping the four ID arrays, but gives no guidance on whether at least one target is required, and the schema marks none of them required.

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 gives a specific verb+resource ("add a note") plus the attachment scope ("history of one or more people, companies, deals or projects"), which clearly separates it from read-side siblings like get_note and list_notes. It stops short of naming an alternative explicitly, but the WRITE-prefixed phrasing leaves no real ambiguity.

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?

"Nothing is sent to the contact" is a useful exclusion that tells the agent this is not a messaging/email action, implying a different tool is needed for actual outreach, and "POST /protocols" anchors the mechanism. However, no sibling is named and there is no explicit statement of when to prefer this over create_task or an update tool, so usage is only implied.

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