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

No annotations are provided, so the description carries the full burden of disclosing behavior. It only says an 'index' exists; nothing about side effects, return values, or whether this is a read-only operation. The tool's behavior is completely opaque.

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 extremely short, which is concise, but it is under-specification rather than purposeful structure. The single phrase adds no actionable information beyond the tool name and is not effectively front-loaded with value.

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?

Despite having zero parameters and no output schema, the tool's core purpose remains unclear. With no annotations and no behavioral disclosure, the description is the only source of context, and it fails to explain what the tool returns or when to invoke it.

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 no parameter documentation burden. The baseline of 4 applies because the description is not required to add meaning beyond an empty 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 'Index of the Mural API' is a noun phrase that identifies a resource but lacks an explicit action. It essentially restates the tool name and does not tell an agent what operation to perform. The sibling tools suggest it could be a directory or reference, but that is left entirely to inference.

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?

There is no guidance on when to use this tool versus any of its siblings. No mention of context, prerequisites, or alternatives is present.

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