webmcp_list_invocations

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

The description explicitly states 'Side effects: none (read-only state access)', which is important behavior disclosure since annotations are not provided. It goes beyond the core purpose to clarify that the tool is safe to call without side effects. It also states the return format with a JSON array and field names. The only minor gap is not mentioning potential error cases or session-specific limitations, but the read-only disclosure is strong.

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 description is concise and well-structured, with three sentences that cover the purpose, side effects, return format, and usage contexts. It front-loads the core function and then adds essential details. There is no fluff or redundancy; each sentence earns its place.

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?

The description is complete given the tool's simplicity. It has a clear purpose, behavior (read-only), return format, and usage guidance. No output schema exists, but the description explicitly lists the fields in the return array, which substitutes for it. All essential information for correct invocation is present.

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 schema description coverage is 100%, so all three parameters are already described in the schema. The description adds no additional meaning beyond what the schema provides, such as the relationship between the status filter and the return list. Since the schema covers the parameters fully, the baseline of 3 is appropriate; the description does not need to compensate.

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 clearly states the tool lists all WebMCP tool invocations with their status, and distinguishes it from webmcp_get_invocation for a single invocation. The verb 'Lists' and specific resource 'WebMCP tool invocations' make the purpose unambiguous, and it differentiates from the sibling tool.

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?

The description explicitly states when to use this tool: to find invocations waiting for user consent (status 'Pending') or to recover an invocationId after losing it. It also names the alternative (webmcp_get_invocation) for single invocation. This provides clear guidance on when to use this tool over alternatives.

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