brain-mcp

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

The description adds valuable behavioral context beyond what annotations provide. While annotations declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, the description specifies that it 'Returns the complete markdown content including frontmatter, plus extracted metadata (type, wikilinks, updated date)' and describes the return format. This provides important implementation details about what data is returned and in what structure.

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 perfectly structured and concise. The first sentence states the core purpose, the second describes the return value, and the Args/Returns sections provide essential details without redundancy. Every sentence earns its place, and information is front-loaded with the most important details first.

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, rich annotations (readOnlyHint, idempotentHint), and the presence of an output schema, the description is complete enough. It explains what the tool does, what it returns, and provides parameter guidance. The output schema will handle return value details, so the description appropriately focuses on purpose and behavior.

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% schema description coverage, the description must compensate but only partially succeeds. It states 'Either a vault-relative path or a note title' which clarifies the param's purpose, but doesn't explain the path format, title matching behavior, or what happens if both are provided. The schema itself has good descriptions for path and title fields, but the overall param object lacks description coverage.

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 ('Read the full content'), target resource ('a specific note'), and identification method ('by path or title'). It distinguishes this read operation from siblings like brain_create_note, brain_update_note, and brain_move_note which are write operations, and from brain_list_notes which lists multiple notes rather than reading one.

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 ('Read the full content of a specific note by path or title'), implying it's for retrieving a single note's content. However, it doesn't explicitly state when NOT to use it or name specific alternatives like brain_search_notes for finding notes by content rather than path/title, or brain_list_notes for getting metadata about multiple notes.

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