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

Annotations already indicate idempotency and non-destructiveness, and the description adds valuable context: it requires the current revision (optimistic concurrency), requires access to both records (permission boundary), and includes a security note about treating CRM values as untrusted data. No contradiction with annotations.

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?

Four short sentences deliver the operation, a key side effect, prerequisites, and a security warning. There is no filler, and the core purpose is front-loaded.

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 mutation tool with no output schema and low parameter coverage, the description covers the important operational context: what it does, what side effects can occur, what inputs are needed, and a safety consideration. It stops short of explaining return/error behavior or all parameter roles, so it is not fully complete.

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 only 14%, so the description must compensate. It partially does by tying expectedUpdatedAt to the 'current contact revision' and makePrimary to 'explicitly make it primary,' but it does not clarify the roles of id versus companyId or explain idempotencyKey.

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?

The description states a specific verb and resource: 'Link or unlink one contact/account association.' It also adds the meaningful nuance that linking may make the association primary, which clearly differentiates this from read-only siblings like get_contact_accounts and other mutation 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?

The description gives useful preconditions ('Requires the current contact revision and access to both records') but does not explicitly say when to choose this tool over alternatives or when not to use it. Usage context is implied rather than directly stated.

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