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

The description discloses two important behavioral traits: partial updates and the fact that already-invoiced periods are never re-issued, with new amounts applying only to future periods. This adds meaningful context beyond the annotations, which only indicate non-read-only and non-idempotent behavior. No contradiction with annotations exists.

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?

The description is two sentences with no filler. It front-loads the purpose and scope, then states the critical invariants. 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 tool with no output schema and minimal annotations, the description provides the key update semantics and the invoicing invariant, but it leaves many field-level details and return/error behavior to inference. It gives a solid first-order understanding without being fully operationally complete.

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 low at 38%, so the description carries part of the parameter-semantics burden. It lists the mutable fields and adds the valuable partial-update rule, but it does not explain fields like due_days, auto_generate, client, or currency beyond their names. This is adequate but not fully compensating for the schema 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 starts with 'Change one schedule by id', giving a specific verb and resource, and then enumerates the editable fields. This clearly distinguishes the tool from siblings like schedule_create, schedule_delete, and schedule_pause without needing to open their schemas.

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 clearly implies an update-to-existing-schedule use case through 'by id' and 'only the fields you pass change'. It does not explicitly name alternatives such as schedule_create for new schedules or schedule_pause/schedule_resume for state changes, so exclusion guidance is implicit rather than explicit.

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