proxy_select

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

With no annotations provided, the description carries the full burden. It discloses that the tool returns the new selection and that Mihomo returns 400 when the proxy isn't in the all-list, which is useful error behavior. This goes beyond a bare 'switch' statement, though it doesn't address permissions or side effects.

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 concise and structured, leading with the main action in one sentence, followed by an Args block that lists parameters and a short behavior/error note. Every sentence provides value and there is no fluff.

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 2-parameter tool with no output schema, the description covers the action, parameter formats, return value, and a key error condition. It doesn't mention what happens if the group doesn't exist, but overall it provides sufficient context for an agent to invoke the tool correctly.

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 schema has no descriptions and 0% coverage, but the description compensates by defining both parameters with examples ('GLOBAL', 'Manual' for group; '🇭🇰香港01 [1×] - Lv.4' for proxy). This adds meaning and helps the agent understand expected string formats, though it could be even more explicit about the exact source of the proxy names.

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 action: 'Switch a Selector/URLTest group to a specific proxy.' This clearly identifies the verb (switch), the resource (group), and the object (proxy). It also distinguishes the tool from sibling tools like proxy_test_group by focusing on selection rather than testing.

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 proper usage by specifying applicable group types (Selector/URLTest) and noting the proxy must be in the group's all-list. It doesn't explicitly mention alternatives or when not to use this tool, but the context is clear enough for straightforward selection tasks.

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