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

With no annotations provided, the description carries the full burden and excels. It discloses the search index is incomplete on large brains, empty results are NOT proof of absence, and a hit is real. It also warns about the upstream issue and billing requirement, giving the agent essential context to avoid false conclusions.

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 three sentences, front-loaded with the core purpose, then followed by the critical caveat and usage guidance. Every sentence earns its place; no fluff or redundancy.

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 (search with known limitations) and the abundance of sibling tools, the description is complete: it states purpose, usage boundaries, and alternatives. The presence of an output schema means return values need not be explained. It leaves no critical information unaddressed.

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 high (83%), so the baseline is 3. The description adds value by clarifying the default search scope ('across thought names and content') and requiring npub for credit billing, which complements the schema. However, it doesn't explain each parameter deeply beyond what the schema already provides.

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 performs 'Full-text search across thought names and content,' using a specific verb and resource. It distinguishes itself from siblings like brain_get_thought and brain_get_thought_by_name by emphasizing it is a search for discovery, not an authoritative existence check.

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?

Provides explicit guidance: 'Use for discovery of older/established thoughts, not as an existence check — verify by ID with get_thought before acting on "not found".' It names the alternative tool (get_thought) and clearly states when NOT to use it, which is exemplary.

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