som_locate

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

With no annotations, the description carries the full burden. It discloses the iterative process, the final box mode, and the accuracy advantage. However, it does not mention side effects (e.g., saving annotated images via out_path), the number of vision calls per round, or potential limitations, leaving behavioral transparency incomplete.

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 two dense sentences with zero filler. The first sentence front-loads the tool's purpose and core algorithm; the second adds a usage guideline. Every clause earns its place, making it highly concise and well-structured for a technical tool.

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 tool has 9 parameters and no output schema, yet the description only explains the high-level algorithm. It does not clarify the return format (pixel vs norm, relative to which image), how the 'box' output is expressed, or how to interpret results after multiple rounds. This is a significant gap for a complex tool, leaving the agent without critical operational details.

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 89%, so the baseline is 3. The description's mention of final modes (box/number/cv) and grid recursion aligns with schema descriptions but does not add new parameter-level semantics. Parameters like grid, rounds, expand, and coords are already well documented in the schema, and the description does not elaborate further.

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 a specific method: Set-of-Mark numbered grid recursive localization. It details the process (overlay numbers, model answers number, iterative crop/zoom, final box output) and contrasts it with direct coordinate localization, distinguishing it from generic locate tools like locate_object or cv_locate.

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 a clear usage context: it is more accurate than direct coordinate output for general VLMs without grounding training (e.g., MiMo). This implies when to prefer this tool. However, it does not explicitly name alternative sibling tools or provide exclusion conditions ('use this when... not when...'), falling short of full explicit guidance.

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