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

With no annotations provided, the description fully discloses behavior: it uses DECKER's execution engine, looks up actual positions (real or virtual), handles mixed positions, and returns a response with execution_mode. It also states the not-found behavior, going beyond what annotations could provide.

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 detailed and every sentence conveys useful information, but it is somewhat verbose with parentheticals and cross-references. It could be tightened slightly without losing the transparency, but it remains well-structured and front-loaded with the primary purpose.

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?

The description covers most aspects: purpose, restrictions, mode selection, mixed positions, and edge cases. The only minor gap is that it doesn't explicitly describe how close_fraction applies when both real and virtual positions exist (e.g., does it close half of each or apply only to one). This is a small ambiguity given the otherwise thorough coverage.

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 provides full descriptions for both parameters (symbol and close_fraction), and the description reiterates that closing can be partial, but adds no new parameter-level details beyond what the schema already states. Given the 100% schema coverage, a baseline score of 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 clearly identifies the action: closes or partially reduces an existing position. It distinguishes itself from sibling tools like place_order by stating it is for closing, not opening, and notes the absence of the crypto-6 restriction. The statement 'No open position for the symbol = a clean not-found response' further clarifies the tool's scope.

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 explains when to use this tool: to close positions, and contrasts it with place_order, noting which restrictions apply. It explicitly says it is safe to call speculatively when no position exists, and mentions the account-linkage requirement for real positions. This is clear, actionable guidance.

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