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

Annotations already declare the write profile (readOnlyHint=false, idempotentHint=false, destructiveHint=false), so the safety picture is covered. The description adds the scope distinction versus crm_add_note but says nothing about auth requirements, whether notes are editable/deletable afterward, or what the write returns, so it contributes only modestly beyond the annotations.

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 and resource, then uses the trailing parenthetical for sibling disambiguation. No filler; every clause 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?

For a simple two-parameter mutation with annotations present and no output schema, the description covers purpose and sibling routing adequately. It is thin on what a contact_id must reference and what happens on success/failure, which a fully complete definition would touch on.

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 0% for both parameters. The description gives useful content guidance for 'note' via the examples, but 'contact_id' is left entirely undocumented and no format or length expectations are set for either field, so it only partially compensates for the coverage gap.

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 ('Add') and resource ('note to a contact'), and explicitly disambiguates from the sibling crm_add_note by noting that one is for a deal. An agent can pick between 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?

The parenthetical 'crm_add_note is for a deal' routes the agent to the correct sibling, and the examples of note content ('what they said, what they want, when to follow up') clarify the intended usage context. It lacks explicit exclusions such as when not to log a note or prerequisites for the contact existing.

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