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

Annotations already declare readOnly=false, destructive=false, idempotent=false, and openWorld=false, so the safety profile is covered structurally. The description adds genuinely new behavioral context that annotations do not carry: the required project_sites:write scope. It stops short of noting any side effects on existing links or duplicate-handling behavior.

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 sentences, front-loaded with the action and followed by the authorization precondition. No filler, no redundancy.

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 simple two-parameter association tool with full schema coverage, full safety annotations, and no output schema, the description covers purpose and the auth requirement adequately. It could be slightly stronger by noting the effect on already-linked pairs, but nothing needed to call it correctly is missing.

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 both parameters (project_id, site_id) are documented in the schema with format and pattern. The description adds no syntax, constraint, or ordering detail beyond that, so baseline 3 is appropriate.

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 clear verb+resource: linking (associating) a site to a project. The operation is unambiguous, but with many sibling association tools (create_contract_site, create_service_area_site, create_vendor_site_assignment, create_project_location), the description does nothing to distinguish this tool from those or explain why a caller would pick it over them.

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?

States the required permission scope (project_sites:write), which is a useful precondition for invocation. However, it gives no when-to-use guidance relative to the many sibling create_* association tools, and no when-not-to-use or alternative routing.

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