close_instance

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It explicitly describes side effects (destructive for secondary instances, special handling for 'default') and the return format (structured JSON with instance_id and removal status). No behavioral aspect is left undocumented.

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 thorough yet every sentence serves a purpose: core action, side effects, return value, usage context, and alternatives. It is front-loaded with the primary verb and resource, and the logical progression aids comprehension without any filler.

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?

This tool has nuanced behavior (different outcomes for default vs. other instances) and no output schema, yet the description covers all necessary context: side effects, return structure, when to use it, and alternatives. An agent can invoke it correctly without needing additional information.

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 description covers 100% of the single parameter, including the critical difference between 'default' and other instances. The description does not add parameter-level detail beyond the schema, so a baseline score of 3 is appropriate. The contextual reinforcement in the description is helpful but redundant with 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 action: 'Closes and stops the specified Chrome instance by id.' It also distinguishes itself from siblings by naming alternatives like stop_chrome and close_tab, so an agent can immediately understand what this tool does that others do not.

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 provides explicit usage guidance: 'Use this to free resources used by sessions created with open_instance.' It also lists alternatives with their distinct purposes, making it unambiguous when to call this tool versus stop_chrome or close_tab.

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