Read the workspace and key

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

Annotations already declare readOnly, idempotent, non-destructive and open-world, so the safety profile is covered; the description adds the valuable disclosure of what the payload contains and that key scope determines write capability, which directly affects planning. It stops short of covering auth failures or error behavior for an invalid key, so it is not fully exhaustive.

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 tight sentences, front-loaded with 'Read-only' and the identity framing, then the enumerated return contents, ending on the actionable 'call it first' guidance. Every clause carries information; the inline domain example earns its space by making 'link domain' concrete.

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, and the description compensates by enumerating exactly what comes back (name, link domain, custom domains, plan, key scope). Combined with annotations covering safety, an agent has everything needed to call it and interpret the result.

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?

The tool takes no parameters, so there is nothing for the description to disambiguate; the baseline for a 0-param tool is 4. The description correctly implies the implicit context (the key itself identifies the workspace) rather than inventing param details.

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?

Names the exact resource (the workspace and the secret key's identity) and enumerates the returned facets: workspace name, link domain, custom domains, plan, and key scope (full/links/read). It is clearly distinct from siblings like list_domains or get_usage because it frames the key's own identity rather than a collection.

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 an explicit trigger — 'Call it first when you need the link domain (for check_app_links) or to know whether the key can write' — naming both the condition and the downstream tool that consumes the result. The agent knows when to reach for this over any other sibling.

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