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

Annotations already indicate it's a write (readOnlyHint=false) and not idempotent. The description adds valuable side-effect context: it explicitly states it does NOT read a provider or send to Slack, and that 'A note never refreshes contact recency' — these are non-obvious behaviors that prevent user confusion. It stops short of detailing permissions or rate limits.

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?

Very concise: five short sentences that pack substantial value, each addressing a distinct aspect (what, evidence quality, source semantics, non-effects, recency caveat). No filler.

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 9-param write tool with no output schema, the description covers the key behavioral surprises and quality guidance. It leaves some parameter details (e.g., occurred_at format, workspaceId handling) to the schema, which is reasonable, but with low schema coverage it could say more about required fields like body nullability.

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 only 11%, so the burden falls on the description. It lists the signal kinds (matching the kind enum) and source link, and clarifies source attribution semantics, but it does not explain occurred_at, company_id, title/body limits, or the optional workspaceId. Baseline 3 is appropriate given partial enum coverage but significant gaps.

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 clearly states the tool appends a dated note/meeting/reply/engagement/risk/milestone with a source link, and enumerates the supported kinds, which matches the kind enum in the schema. It does not explicitly differentiate from list_signal_events, but the write verb 'Append' makes the create-vs-read distinction intuitive against the 'list_' sibling.

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 description offers a quality constraint ('Use evidence, not assumptions') and a caveat about attribution ('Source names are attribution, not provider verification'), which guides proper usage. However, it does not say when to use this vs. list_signal_events or add_company_contact, nor does it specify preconditions like required company existence.

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