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

Annotations already establish this as a safe read-only, closed-world operation, so the safety burden is lifted. The description adds the ordering guarantee ('newest first by date') and the filterable dimensions, which are useful beyond annotations. It omits any mention of pagination behavior, result caps, or what include_deleted actually surfaces — a real gap for a list endpoint, but not a contradiction.

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?

Two compact sentences with no filler. Ordering and filtering — the two facts an agent most needs — are front-loaded, and the routing note is placed last where it belongs as a secondary concern.

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-value explanation is not required, and the description covers ordering plus the two primary filter axes. But for a 7-parameter list tool with 0% schema coverage, the complete silence on pagination (limit/cursor) and on include_deleted leaves the agent unable to page or control soft-deleted visibility without guessing.

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 0%, so the description carries the full burden, and it only accounts for two of the seven parameters (since/until as 'date range', paid_by as 'payer'). limit, cursor, include_deleted, and the required group_id receive no semantic explanation anywhere. The paid_by dual shape (agent_id vs handle) is also left undocumented.

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 the resource (expenses of a group), the ordering (newest first by date), and the filter axes (date range or payer). The verb 'list' comes from the name, which is acceptable, and the pointer to get_expense for splits/history helps distinguish it from a sibling. It stops short of a fully explicit verb+scope statement but is clearly interpretable.

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 clause 'Splits and history are in get_expense' routes the agent to the detail sibling, which is genuine usage guidance. However, there is no statement of when to prefer this tool over list_payments or other list_* siblings, and no mention of pagination expectations for large result sets. Guidance is implied rather than explicit.

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