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

The annotations already declare readOnlyHint and idempotentHint, and the description adds valuable context beyond that: it explicitly promises credentials are never returned, enumerates the visible fields, and documents the not_found failure condition for unknown or invisible IDs. This fully covers behavioral expectations without contradicting the 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?

Three tight sentences with no filler: the resource and return fields come first, the ID-finding guidance follows, and the safety/failure behavior closes the description. Every sentence 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?

For a single-parameter read tool with no output schema and strong annotations, the description is complete: it names the parameter source, enumerates return fields, discloses credential exclusion, and states the error condition. Nothing essential is missing for an agent to call it correctly.

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%, so the baseline is 3, but the description adds meaningful value by naming connector_id as the lookup key and telling the agent to source it from list_connectors. It also clarifies that an invalid or invisible ID leads to not_found, which enriches the parameter's semantics beyond the schema description.

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 ('Fetch'), the exact resource ('one saved connector by connector_id'), and enumerates the returned fields, which clearly distinguishes it from list_connectors, create_connector, update_connector, and delete_connector. The explicit exclusion of credentials further sharpens the purpose.

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?

Directly instructs the agent to use list_connectors to find IDs, which is the key prerequisite and routing guidance. The failure mode for unknown or invisible IDs also helps the agent decide when this call is appropriate.

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