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. The description adds valuable behavioral context beyond annotations: it specifies that it returns 'matching notes with context snippets' and 'Returns an error message if no results found,' which clarifies output format and error handling not covered by 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 well-structured and front-loaded with the core purpose in the first sentence. Each subsequent sentence adds value: use cases, parameter overview, and return details. There is no wasted text, and it efficiently conveys necessary information.

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 moderate complexity (search function), rich annotations (covering safety and idempotency), and the presence of an output schema (which handles return values), the description is complete enough. It covers purpose, usage, behavioral traits, and parameter overview without needing to duplicate structured data.

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 description coverage is 0%, but the description includes an 'Args' section that explains the 'params' object contains 'Search parameters including query, optional folder scope, and limit.' This adds some meaning beyond the schema, but does not detail individual parameters (query, folder, limit) or their interactions. With 0% coverage, it partially compensates but not fully.

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 ('Full-text search across the Brain Obsidian vault'), resource ('notes'), and scope ('Searches note content for the given query string'). It distinguishes from siblings like brain_list_notes (which lists without search) and brain_find_backlinks (which finds references).

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 clear context for when to use this tool ('Useful for finding notes about a topic, locating references, or discovering related content'), but does not explicitly state when not to use it or name alternatives among siblings (e.g., brain_list_notes for unfiltered listing).

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