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

Annotations already declare non-readonly, non-destructive, non-idempotent, and closed-world behavior. The description adds useful context beyond that: the note is internal and never sent to the prospect, and `lead_note_update` replaces the whole body. It does not address retry/duplicate behavior despite `idempotentHint=false`, so it falls short of a 5.

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 sentences, front-loaded with the core action, followed by the key exclusion and the update alternative. Every sentence carries useful routing or behavioral information with 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 simple two-parameter note-creation tool with annotations and no output schema, the description covers purpose, exclusions, and the follow-up update path. Nothing critical is missing for correct invocation.

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 in the schema (`leadId` from `lead_list`, `content` as body text). The description adds no parameter-specific syntax, constraints, or examples beyond what the schema already provides, so the 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?

States a specific verb and resource: 'Write an internal note on a lead.' It also explicitly distinguishes this from messaging the prospect and from lead_note_update, so an agent can identify the tool without opening the 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?

Explicitly says this is not a way to message anyone and names `message_send` as the alternative for prospect messaging. It also directs the agent to `lead_note_update` when changing an existing note, covering both when-not and alternative paths.

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