m3_index

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

With no annotations provided, the description carries the full burden. It states 'Read-only catalog metadata; never returns tool output', clearly indicating safety and no side effects. This is sufficient for a catalog tool, though it lacks details on rate limits or auth, which are less critical here.

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 at 4 sentences, each serving a clear purpose: stating output, providing usage advice, declaring read-only behavior, and listing domains. It is front-loaded with the core function and highly efficient.

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 no output schema and 0% schema description coverage, the description is mostly adequate but misses details on the timeout and database parameters. It covers purpose, usage, behavior, and domains well, but the parameter gap reduces completeness.

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 schema description coverage is 0%, so the description must explain all parameters. It partially explains the domain parameter with 'optionally one domain', but completely omits the timeout and database parameters, leaving them unexplained. This is a significant gap.

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 tool's purpose: 'List m3 catalog tools (optionally one domain) as structured rows'. It specifies the output fields and distinguishes itself from the sibling m3_call by advising to use this tool 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 provides explicit usage guidance: 'Use this to discover the exact args for any tool before calling it via m3_call — cheaper than a failed call'. It also lists the available domains for filtering. However, it does not specify when not to use it or mention alternatives beyond m3_call.

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