m3_index

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

Even without annotations, the description explicitly states it is 'Read-only catalog metadata; never returns tool output,' which discloses non-destructive behavior. It also hints at low cost. While it doesn't detail rate limits or authentication, the simple read-only nature is transparent enough for a listing tool.

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 sentences front-loaded with the main action and output format. Every sentence adds essential information without redundancy. It achieves high information density in minimal space.

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 adequate coverage of purpose, output format, and domain list, the description fails to explain two out of three parameters (timeout and database). Without output schema, the verbal description of output mitigates that gap, but missing parameter documentation leaves the tool incomplete for the simplicity level.

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 coverage is 0%, so the description must explain parameters. It only explains 'domain' (optionally one domain), but completely omits 'timeout' and 'database' from the description. The agent receives no guidance on these parameters, so the description adds minimal semantic value beyond the 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 clearly states it lists m3 catalog tools as structured rows, which is a specific verb+resource. It distinguishes itself from sibling tools like agent_list or files_search by focusing on tool metadata discovery, explicitly stating its role in discovering args before calling m3_call.

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 explicitly says 'Use this to discover the exact args for any tool before calling it via m3_call — cheaper than a failed call.' This provides clear when-to-use guidance and an implicit alternative (blind calling). It also clarifies it is read-only and never returns tool output, setting expectations.

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