set_fill_color

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

No annotations are provided, so the description carries full burden. It states the tool sets a solid background fill on every cell in the range, which is transparent but does not disclose behavior for invalid range, existing fills, or performance. Adequate but minimal.

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, with two sentences and no filler. Purpose is front-loaded, and color instructions are clearly separated. Every sentence earns its place.

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 simplicity and lack of output schema, the description is fairly complete for setting fill color. It explains how to specify and remove fill, though it could note that it replaces existing fill. Slightly above adequate.

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?

With schema_description_coverage at 0%, the description adds value for the 'color' parameter (hex names, 'none' to remove) but does not explain 'range' or 'session_id'. Partially compensates but not fully.

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 verb 'Set' and resource 'solid background fill on every cell in a range', making the tool's purpose immediately obvious. It distinguishes from sibling formatting tools like set_borders or set_font by specifying 'fill color' as the target.

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 color format options and removal instructions, but does not explicitly state when to use this tool versus alternatives like apply_style_preset or clear_range. Usage guidance is implied but lacks explicit when-not or alternative comparisons.

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