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

Annotations already establish the safety profile (readOnlyHint=false, destructiveHint=false, idempotentHint=true), and the description adds genuine context on top: `paused` freezes only this lead, and `isExcluded` removes from sending 'without deleting the record', which clarifies the non-destructive boundary. It stops short of covering side effects like what happens to an in-flight sequence when email is changed, or whether repeat updates are no-ops despite idempotentHint.

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?

Front-loads the core purpose in the first clause and packs the routing hints into two efficient sentences with zero filler. It is dense — the second sentence stacks three exclusions — but 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?

For a 13-parameter mutation with no output schema, the description covers purpose, scope, alternatives, and the semantics of the two highest-risk flags. Minor gaps remain around update side effects and no-op/idempotency behavior, but nothing an agent needs in order to select and call it correctly is missing.

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 all 13 parameters including the nested customFields are already documented, making 3 the baseline. The description paraphrases `paused` and `isExcluded` and gestures at merge-field data, but adds little semantic detail the schema does not already carry, and says nothing about `seen`, `isInterested`, or `personalization`.

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+resource ('Edit a lead') and immediately enumerates the concrete edit classes: contact details, sequence pause, exclusion, merge-field data. It then explicitly names the three siblings it is not (campaign_set_status, lead_move, conversation_update), so an agent can route without opening any 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?

Gives both when-to-use ('correct contact details, pause its sequence, exclude it from sending, or attach merge-field data') and when-not, with the correct alternative named for each excluded case. The scope constraint 'Scope is one lead' further bounds use.

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