Fetch Actor MCP tool list

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

Discloses traits the annotations cannot express: no caching, re-querying the server each call, API-token connection, potential start of a Server Actor run held until idle timeout, and per-event billing for multi-tenant servers. This usefully explains why readOnlyHint is false for a 'list' operation. The main omission is that the returned list's shape or failure modes (e.g. what happens when the Actor exposes no MCP server) aren't hinted at beyond the field list.

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?

Front-loaded with the core purpose, then a distinct USAGE block and an example. Every sentence carries information — the caching, token, run-lifecycle, and billing notes all matter for correct invocation, and nothing is repeated.

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?

Output schema exists so return values need no explanation, and the description still summarizes the returned fields. Cost/lifecycle side effects and the sibling relationship are covered. Minor gap: no guidance on prerequisite connectivity or error cases, though this is largely implied by the token/run notes.

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% and the single 'actor' parameter is fully documented in the schema, so the description adds only the implicit framing that the parameter identifies an MCP server Actor. With the schema doing the heavy lifting, 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?

States a specific verb and resource ('List an Actor's MCP tools') and enumerates exactly what is returned (name, description, input schema, annotations, metadata). It also explicitly contrasts with the sibling call-actor-mcp-tool, which calls one of them by name, so an agent can pick between them without opening either schema.

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 a concrete trigger ('when the user asks which MCP tools an Actor provides') plus the preparatory case ('before calling one of them'), and includes a usage example. Alternatives are addressed by naming call-actor-mcp-tool as the follow-up action.

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