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

Annotations already cover the safety profile (readOnlyHint=true, openWorldHint=false), so the bar is lower, and the description still adds real context: the call is 'Free' (no credit cost) and it enumerates the returned fields. It does not say whether the gateway must exist or what happens on an unknown gw_id, but the added cost and content disclosure is meaningful.

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?

One tight sentence that front-loads the core purpose and appends the field list and the 'Free' qualifier without padding. Every clause carries information.

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, so enumerating the returned fields (forwarding target, Passport requirement, rate limit, call counts) is exactly the right compensation. The only gaps are error behavior and the boundary versus gateway_list/gateway_stats, which is a minor omission for a simple read 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 coverage is 100% — the single parameter gw_id is documented as a 'gw_... ID' in the schema — so the schema carries the burden. The description adds nothing about the identifier's format or lookup semantics, making the baseline 3 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 specific verb and resource: it returns a gateway's public description, enumerated as forwarding target, Passport requirement, rate limit, and call counts. However it never distinguishes itself from the closely related siblings gateway_list and gateway_stats, so an agent must infer the boundary itself.

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?

Usage is only implied: the required gw_id and the 'public description' framing suggest fetching metadata for one known gateway. No explicit when-to-use, when-not, or alternative (e.g. gateway_list for enumeration, gateway_stats for metrics) is named, so the agent must guess.

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