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

Annotations already declare readOnlyHint=true, idempotentHint=true and destructiveHint=false, so the safety profile is covered. The description adds genuinely non-obvious semantics beyond that: the mutual exclusivity of the three linked IDs per row, and that links never contribute to committed cost because the PO is charged only to its own project_id/work_order_id, which guards against double-counting mistakes.

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?

Three short sentences, front-loaded with the definition of the resource before the cost caveat and the filtering hint. No filler or repetition, though the cost sentence is somewhat tangential to selecting the tool.

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 usefully characterizes the returned rows (one of three linked IDs each) and confirms the operation is a reference-only listing. For a zero-required-parameter, fully documented read tool this is close to sufficient; only the relationship to singular/alternate list siblings is unaddressed.

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 every parameter carries its own description (including UUID formats and the automatic multi-page fetch on page/per_page), so the schema does the heavy lifting. The description only adds that the four IDs are all valid filters, which is a modest restatement of what the schema already documents.

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 (List) and resource (purchase order links) and defines what a link actually is: 'the extra records a purchase order is linked to for reference', with each row containing exactly one of work_order_id, pm_schedule_id or project_id. This is much clearer than a bare restatement, though it does not name a sibling (e.g. get_purchase_order_link or list_purchase_orders) to sharpen the boundary.

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 closing sentence 'Filter by any of those four IDs' implies how to narrow results, and the cost note hints the data is informational only. However, it never states when to reach for this tool versus get_purchase_order_link (singular) or list_purchase_orders, and no exclusions or prerequisites are given.

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