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

Annotations already declare readOnly, idempotent, non-destructive, closed-world, so the safety profile is covered; the description still earns credit by adding the full channel vocabulary, the null-when-unrecorded semantics, and the fact that results are rendered in the caller's timezone. It stops short of disclosing pagination behavior or result volume limits, which the schema only partially covers.

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 dense sentence that front-loads the actor/record/channel/time/diff axes and closes with the timezone caveat. Every clause carries information an agent cannot get from the schema alone.

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?

An output schema exists, so return-shape explanation is unnecessary, and all four optional parameters are fully documented in the schema. What remains missing is selection guidance against the many sibling read tools, which matters given how many listing tools share this namespace.

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 coverage is 100% — days, page, record_id, and record_type all carry their own descriptions including defaults and maxes. The description adds nothing parameter-specific (the timezone note describes output, not an input), so the baseline 3 applies.

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 a precisely scoped resource: change history across CRM records, with actor, channel, timestamp, and field-level diffs. That clearly separates it from the entity-listing siblings (list-companies-tool, list-people-tool), but the description never names an alternative, so the differentiation is implicit rather than stated.

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 implies the use case (auditing who changed what and when) but gives no explicit when-to-use / when-not-to-use guidance and never routes the agent toward or away from siblings such as get-crm-summary-tool or the per-entity list tools. Usage is inferable, not stated.

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