webmcp_get_invocation

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

With no annotations provided, the description fully bears the behavioral disclosure burden. It explicitly states 'Side effects: none (read-only state access)' and details the return JSON structure, including status values and output/errorText. It also explains the source of invocationId in a timeout error scenario, adding useful behavioral context.

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?

Every sentence earns its place: purpose, side effects, prerequisites, return format, usage, and alternative are covered in a compact, well-sequenced paragraph. The most critical information (what it does and side effects) is front-loaded.

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 the description correctly provides the return shape (toolName, frameId, input, status, output/errorText). It also covers prerequisites, side effects, usage context, and an alternative. For a polling tool with no nested objects and clear parameters, everything an agent needs to call it correctly 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?

Schema coverage is 100%, so all three parameters already have descriptions. The tool description adds minimal value beyond this: it repeats the origin of invocationId (already in schema) and does not elaborate on tab_id or instance_id. Per the baseline rule, a score of 3 is appropriate when the schema handles parameter documentation.

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 opens with a precise verb+resource statement: 'Returns the current status and result of a WebMCP tool invocation by its invocationId.' It explicitly names the alternative webmcp_list_invocations, so an agent can immediately distinguish it from siblings without inspecting schemas.

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 gives explicit guidance: 'Use this to poll a long-running invocation ... without blocking' and names the alternative (webmcp_list_invocations) with the condition for choosing it. It also states the prerequisite that invocationId must come from webmcp_invoke_tool, leaving nothing to inference.

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