select_target

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

There are no annotations, so the description carries the full burden. It discloses important behavior: the selection persists across all later model operations, the instance is validated as online, and the previous silent default-to-first-instance behavior is gone. It does not say what happens when validation fails or which instance is currently selected, but it is substantially better than a bare mutation description.

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 sentences, zero filler, focused on the main point first: the lock is front-loaded, and the conditional requirement follows. Slightly dense punctuation but structurally sound.

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 two-parameter state-setting tool with no annotations and no output schema, the description covers the essential unknowns: persistence of the selection, the online validation, and the mandatory ordering when multiple instances are online. An agent has enough information to call this correctly and in the right sequence.

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 100%, so model and instance are already documented in the schema, including the default of 1. The description mentions the multi-instance context that makes 'instance' relevant, but it adds no format or semantics beyond what the schema states; baseline 3 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 states a specific verb+resource: locking ('锁定') a target instance that governs all subsequent model operations. It is clear what state changes. It does not, however, explicitly distinguish itself from the sibling get_target, leaving the agent to infer that get_target only reads while select_target sets.

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 gives explicit when-to-use guidance: when multiple instances are online, this tool must be called first, before any model operation, because the server no longer falls back to instance 1 by default. It never states a when-not-to-use case or points the agent to list_instances first, but the usage condition is unusually strong.

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