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

Annotations already declare readOnlyHint=true, so the safety profile is covered. Beyond that the description confirms the REST endpoint but says nothing about what a user record contains (the very IDs it claims to resolve), pagination behavior, or response shape. With annotations carrying the safety burden, this is adequate but thin.

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 short clauses, front-loaded with the verb+resource, then the operational motivation, then the endpoint. No filler; every fragment 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?

There is no output schema, so the description should carry some of the return-value burden; it only says it lists users without indicating that records expose the user IDs needed to satisfy the stated purpose. For a simple read with 100% schema coverage this is passable but incomplete.

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%, and all three parameters (top, skip, count_total) are documented in the schema including the count_total response-shape change. The description adds no parameter guidance, so 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?

States a specific verb and resource ('List the users in the Insightly instance') and adds the underlying endpoint GET /Users, so the operation is unambiguous. It partially differentiates from siblings by implying this is the ID-resolution source, but never contrasts itself with insightly_get_current_user, which an agent could easily confuse it with.

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 a concrete reason to call it — resolving OWNER_USER_ID / RESPONSIBLE_USER_ID before writes — which is real, actionable context. It stops short of an explicit alternative ('use get_current_user for the caller's own identity'), so the routing to siblings is left partly to inference.

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