contacts_discover

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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description usefully adds that this is a discovery/meta step that 'reveals hidden tools' and must be invoked first. However, enumerating 'create, update, delete' as ops alongside a readOnly annotation creates real potential for the agent to mistake this for a mutating call, and the return structure of the catalog is never characterized.

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?

The core instruction is front-loaded in the first clause, and the workflow ordering follows immediately. The long semicolon-delimited ops enumeration is dense and its value is questionable, but the description is not padded with filler.

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?

With no output schema, the description carries the burden of explaining what discovery returns, and 'lists the catalog and reveals its hidden tools' plus the ops enumeration gives the agent a usable roadmap. It still does not describe the shape of the catalog response or how a 'hidden tool' is addressed by name, leaving a modest gap for a meta-tool.

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% ('query: Filter keyword'), so the schema already documents the single optional parameter. The description never mentions that query filters the catalog listing, so it adds no semantic value beyond the structured field; 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?

The description states a specific action ('lists the catalog and reveals its hidden tools') on a specific resource (contacts), and distinguishes itself from siblings like discover_all and gmail_discover by scoping to the contacts domain. The trailing 'Ops' enumeration is confusing because it lists downstream operations (create/update/delete) rather than what this call does, muddying the otherwise clear 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?

Explicit sequencing guidance is given: 'call first, then call the tool by name.' That tells the agent exactly when this tool belongs in the workflow and what follows it. It does not name a competing sibling (e.g., discover_all) or state when not to use it, keeping it short of a 5.

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