list_local_icons

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

With no annotations, the description carries the behavioral burden. It explains where the folder lives, how paths are resolved, and how labels are derived (file name without extension). It does not specify the return shape or what happens if the folder is missing, but for a read-only listing tool the disclosed behavior is substantial.

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?

Three sentences lead with the action and then provide only valuable context: the manual download workflow, label semantics, and folder resolution. No filler or redundant restatement of the tool name.

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?

For a parameterless tool with no output schema, the description is comprehensive: it states what is listed, how labels are derived, where files are stored, how to override the location, and how the result is used with sibling tools. Nothing an agent needs to decide whether to call it is missing.

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 tool has zero parameters, so there is nothing for the description to add beyond the schema. The mention of the environment variable is relevant configuration context, not a parameter, and the baseline of 4 applies.

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 first sentence uses a specific verb and object: 'List the local custom-icon folder and the labeled image files in it.' It is unambiguous about what the tool returns and mentions the label-to-filename convention, which distinguishes it from the sibling find_masters and drop_shape tools.

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 gives a clear workflow: labels found here can be placed with drop_shape('<label>', x, y) when Visio has no built-in master, and it notes the folder location and VISIO_MCP_ICONS_DIR override. It does not explicitly list when not to use this tool, but the usage context is clear enough.

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