Chat with a model via Zerouter

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

Annotations only declare readOnlyHint=false and openWorldHint=true, so the description carries real weight by disclosing the per-model-family routing (Claude/Kimi -> /v1/messages, GPT/Grok/Codex -> /v1/responses, others -> /v1/chat/completions) and the API-key auth requirement. It does not disclose rate limits, error behavior, or what a response contains, keeping it below a 5.

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 tight sentences, front-loaded with the core action before routing mechanics and the auth prerequisite. The middle routing sentence is dense but every clause conveys useful model-to-endpoint mapping; nothing is redundant.

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 no output schema and seven parameters, the definition should describe the shape of what comes back (generated text, token usage, routing/endpoint used) so an agent can plan downstream steps. Routing, auth, and parameters are covered well, but the return value remains unspecified.

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 86%, so the documented parameters already stand on their own. The description still adds meaning by explaining how the 'endpoint' override interacts with automatic routing and which models map to which route, going beyond the bare enum values.

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 ('send a prompt or message list to any Zerouter model') and immediately distinguishes itself from the get_pricing/list_models/compare_models siblings, which are informational rather than generative. The automatic routing detail further narrows what this tool uniquely does.

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?

Usage context is implied rather than stated: the description explains routing and the ZEROUTER_API_KEY prerequisite, but never says when to choose this tool or when not to. Since the three siblings are clearly different function categories, the omission is minor, but no explicit alternative guidance is given.

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