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

Goes well past the annotations by disclosing the silent-failure mode (wrong/read-only field names are ignored without error), the mitigation (reply re-reads and shows stored values, so verify), and an external side effect consistent with openWorldHint: syncing accounting records to QuickBooks/Xero and converting leads into synced customers. No contradiction with destructiveHint=true — the description clarifies mutation scope rather than denying it.

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 "WRITE:" and the PATCH distinction, then layers hazards in order of importance. Dense but every clause carries risk information; the trailing endpoint path is the only mildly redundant element given the tool name.

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?

With no output schema, the description correctly explains what the response contains (re-read stored values of the sent fields) and tells the agent to check them. For a nested-object, side-effect-bearing mutation tool, all the call-shaping information an agent needs is present.

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% and both the case-sensitivity of `fields` and the `_RecordID` integer convention are already documented in the schema, so the description largely restates them. It reinforces the silent-ignore risk rather than adding new syntax or format detail, 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?

Opens with an explicit verb+resource+scope: "WRITE: changes fields on one record" and immediately qualifies it as PATCH semantics ("only the fields you pass change"). An agent can distinguish this from method_create_record and method_get_record 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 concrete operating conditions: linked fields must be set via `_RecordID` integers, accounting records trigger a QuickBooks/Xero sync, and "There is no delete tool" implicitly bounds what this tool is for. It does not explicitly route the agent to create_record for new records or name when this should be avoided, so it stops short of full when/when-not guidance.

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