brain-mcp

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

Annotations already provide readOnlyHint=true, destructiveHint=false, idempotentHint=true, and openWorldHint=false, covering safety and behavior. The description adds value by specifying the return content (folder layout, note counts, MOC - Home) and its use for navigation, enhancing context without contradicting annotations.

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 front-loaded with the main purpose, followed by usage guidance and return details in three clear sentences. Each sentence earns its place by providing essential information without redundancy, making it efficient and well-structured.

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 complexity is low (0 parameters, read-only), annotations cover behavioral traits, and an output schema exists, the description is complete. It explains what the tool does, when to use it, and what it returns, without needing to detail parameters or output values further.

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 0 parameters and 100% schema description coverage, the baseline is 4. The description appropriately omits parameter details, as none are needed, and focuses on the tool's purpose and output, adding no unnecessary information.

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 specific action ('Get a high-level overview') and resource ('vault structure'), distinguishing it from siblings like brain_list_folders or brain_list_notes by emphasizing the 'overview' aspect and including MOC - Home content for navigation.

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?

It explicitly states when to use this tool ('as a starting point for exploring the vault') and implies alternatives by mentioning folder statistics and note counts, which could be obtained via other tools like brain_list_folders or brain_list_notes, though not named directly.

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