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

Annotations already declare readOnlyHint=true, so safety is covered. The description adds real value beyond that by disclosing the underlying endpoints (GET /api/v3/contracts vs /contracts/customer/{customerId}), which explains the two operational modes. It does not discuss pagination behavior, though the schema covers page/items_in_page.

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 what the tool returns, then the filtering rule, then endpoint detail. Every sentence carries information; nothing is padded.

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 read-only list tool, the description covers the resource, the returned attributes, and the filter mode. With no output schema, mentioning rates and billing periods is helpful; only pagination behavior is unaddressed, which is a minor gap given the schema fields.

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 100%, so all three parameters are already documented in the schema. The description only restates the customer_id behavior ('Only this customer's contracts' vs 'Pass customer_id for one customer's contracts'), adding no syntax or format detail beyond the schema baseline.

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 (service contracts), and enumerates the contract types (retainer, block hours, hourly, remote monitoring) plus what fields are returned (rates, billing periods). No sibling tool covers contracts, so an agent can immediately distinguish it from the ticket/customer/agent tools.

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?

Explicitly tells the agent when to pass customer_id ('Pass customer_id for one customer's contracts'), clarifying the single-customer vs all-customers modes. It stops short of naming when NOT to use this tool or naming alternatives, but the usage condition is clear.

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