list_models

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

With no annotations, the description carries the full burden. It transparently describes the read-only nature ('List') and details the returned data, including a caveat that text-only models reject image attachments. It omits error or pagination behavior, but for a simple zero-parameter list operation, this is quite transparent.

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 two sentences, front-loaded with the primary action, and every word contributes. It avoids redundancy with the empty schema and efficiently conveys the return structure and a behavioral caveat.

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?

As a zero-parameter, read-only list tool with no output schema, the description fully covers what the tool does, what it returns, and how the output connects to the one sibling tool (execute_prompt). There is no missing critical information for an agent to decide when to use it.

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 tool has zero parameters, so there is no parameter schema to describe. The description adds value by explaining what the returned fields mean (model id for execute_prompt, input modalities), which is the relevant semantic context. Baseline 4 for zero parameters is appropriate.

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 specific verb 'List' and a clear resource: 'supported model providers and the models available under each.' It also explains the return structure, making the tool's purpose distinct from the sibling execute_prompt, which is implicitly for running prompts.

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 indicates the primary use by stating that the provider-specific model id is 'to pass to execute_prompt', which tells the agent how the output should be used. It does not explicitly say 'use this before execute_prompt' or exclude other tools, but given only one sibling, this clear linkage earns a 4.

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