Tool manifest

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

Annotations already declare readOnly, idempotent, non-destructive, and closed-world behavior, so safety is covered. The description adds real behavioral context beyond that: the default response contains names only, and enabling descriptions costs tokens, letting the agent reason about output size.

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 short sentences, front-loaded with what the tool returns, then the recommended usage, then the optional parameter. Every sentence carries information and nothing is padded.

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 an output schema present, return values need not be explained, and annotations cover the safety profile. The description covers scope, defaults, and cost; only minor details (e.g., how grouping keys are structured) are left implicit.

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% and both parameters are already documented there, so the baseline is 3. The description largely restates the include_descriptions effect ('one-line summary per tool' / default false) and adds nothing about the server filter's matching semantics.

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 ('List the upstream tools this gateway currently exposes') plus the grouping scope ('grouped by server') and the default output shape (names only). It is clearly distinguishable from sibling tools like mcptoon_servers, which enumerates servers rather than exposed 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?

Explicitly tells the agent to read this compact view 'instead of pulling every full schema,' which is real when-to-use guidance, and it explains when to pass include_descriptions (one-line summaries) versus keeping the small default. It stops short of naming a specific alternative sibling tool or stating exclusions.

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