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

Annotations already declare the non-destructive, non-idempotent, non-open-world profile, so the bar is lower. The description still adds real behavioral content the annotations lack: the write is an append (nothing overwritten) and the note is visible in the CRM and to the member, which is a meaningful audience/side-effect disclosure.

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?

One sentence, front-loaded with the action and its effect, with the use cases trailing as supporting context. Nothing is redundant.

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?

Output schema exists and parameters are fully documented, so the description need not explain return values. It covers purpose, audience, and append semantics; only failure behavior (invalid contact_id, permission errors) is unaddressed, which is minor.

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% and both parameters are documented there, including the contact_id provenance from find_contact/list_contacts/search_leads. The description only reinforces that the target is a contact timeline; it adds no length, formatting, or source rules beyond the schema.

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?

Names a specific verb (append) and resource (a note on a contact's timeline), and states the resulting effect — visible in the CRM. This clearly separates it from siblings like add_tag, send_email, or update_contact, which write different things.

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?

Offers three use cases (handoffs, call summaries, member-facing context), which implies when to reach for it, but never says when not to use it or which sibling to prefer for structured field changes (update_contact) or notifications (send_email). Usage is suggested, not routed.

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