spine_preview_set_session

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 only writes session state and does not write Spine JSON, and explains the effect on preview layers. However, it lacks details on side effects, error behavior, or required authentication, making it moderately 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 concise, consisting of three short sentences that clearly state the purpose, effect, and limitation. Every sentence adds value without redundancy, making it efficient for an agent 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?

Given the tool's complexity (10 parameters, nested objects, no output schema), the description is minimal. It does not explain return values, success criteria, or provide usage examples. Compared to sibling tools with similar complexity, this description lacks completeness for an agent to use it effectively.

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 has 10 parameters with only 40% coverage (4 described). The description does not add meaning beyond the schema; it only provides a general purpose statement. For example, parameters like animation, skin, speed, etc., have no additional context in the description, leaving the agent with limited guidance.

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 purpose: setting an Agent-driven preview session state with specific resources (JSON, atlas, animation, operation instructions). It explicitly distinguishes from write operations by stating '只写会话状态，不写 Spine JSON', differentiating from sibling tools like spine_preview_clear_session and spine_preview_get_session.

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 context (updating preview session without writing files) but does not provide explicit when-to-use or when-not-to-use guidance. Sibling tools exist for clearing and getting sessions, but no direct comparison or exclusion criteria are mentioned.

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