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

With no annotations, the description carries the full burden and delivers: Euvra re-plans the route and rejects caller-supplied provider IDs/endpoints/tool names, possible NO_ROUTE/AUTH_REQUIRED/BLOCKED outcomes, a 0.01 USDC x402 payment requirement with a fallback payment-requirements response, and an explicit warning not to claim success before confirmation. This is unusually rich disclosure of side effects, costs, and failure modes for a mutation tool.

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-loads the purpose, then flows through alternatives, inputs, routing constraints, failure modes, and payment. It is somewhat long at eight sentences and repeats the provider-selection constraint twice, but nearly every sentence carries distinct operational 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?

For a mutation tool with an output schema, the description supplies everything an agent needs: input shape, sibling routing, routing-immutability, error codes, and payment/auth prerequisites. Return values are properly left to the output schema.

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 the query and arguments semantics are already fully documented in the input schema, and the description largely restates them ('a specific natural-language query... and an arguments object'). The added value is minor, so the 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 ('Execute a real action using a live MCP provider selected by Euvra') and clearly separates itself from its siblings by naming discover_capabilities and compare_capabilities as the research/comparison tools. An agent can distinguish this as the execution step without opening any 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?

Explicitly states when to use it ('only when the user wants the action performed, not merely researched or compared') and routes the agent to the two named alternatives for the non-execution phases. Nothing is left to inference.

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