List available models

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

With no annotations, the description must carry behavioral transparency. It does add a notable behavioral guarantee—'Never returns API keys'—and clarifies the source ('configured in opencode'). However, it does not mention pagination, error behavior, or other operational details that might affect an agent's expectations.

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?

Two tight sentences: the first states the core function and output format, the second gives a parameter hint and a security guarantee. No wasted words; information is front-loaded and easy to parse.

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 simple read-only listing tool with fully documented parameters, the description covers the essential context: what is listed, how to filter, and a key safety property. It does not require a return-value explanation since no output schema exists, and the schema covers parameter details. Slightly more behavioral context could nudge it to 5, but it is adequate as-is.

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 input schema already provides 100% description coverage for all three parameters. The description only adds a redundant note to use 'filter' for narrowing, which is already clear in the parameter description. No additional semantic value beyond the schema.

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's function with a specific verb ('Lists') and resource ('providers and models configured in opencode'), and explains the output format ('provider/model' IDs). This distinguishes it from sibling tools like opencode_set_model or opencode_agents, which have different purposes.

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 implies usage (list models to see available options) and offers a hint on 'filter', but it does not explicitly state when to use this tool versus alternatives or when not to use it. It lacks exclusionary guidance such as 'use opencode_set_model to change the model'.

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