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

The description adds significant behavioral details beyond the annotations: it discloses the ranking formula ('cosine similarity × confidence × importance'), the access scope ('reads your vault only — other agents cannot access it'), and prerequisites ('Requires API key'). It also states 'FREE always,' which is a cost-related trait. These are valuable operational details not present in the 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 exceptionally concise and well-structured. It starts with the core purpose, then explains output ranking, then adds access/cost details. Every sentence provides distinct value with no fluff or repetition. It is front-loaded with the most important 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?

Despite having no output schema, the description adequately explains return values ('ranked memories'), ranking logic, and access restrictions. It covers the essential aspects for a search tool with only two parameters, including authentication requirements. It feels complete for the tool's complexity level.

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 input schema already provides descriptions for both parameters (q and limit) with a coverage of 100%. The description does not add further parameter-level explanation, but it provides context about the search behavior (semantic, ranked) that indirectly supports the meaning of q. Since schema coverage is high, a baseline of 3 is appropriate.

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 function: 'Semantic vector search across your private vault.' This uses a specific verb ('search') and resource ('vault'), and distinguishes it from siblings like x711_vault_write and x711_web_search. It also specifies what it returns ('ranked memories') and the type of content ('facts, insights, and skills'), making the purpose unambiguous.

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 by explicitly targeting the 'private vault' and contrasting with general web/data search. It implies the tool is for querying the agent's accumulated knowledge, and mentions 'reads your vault only' which sets expectations. However, it doesn't explicitly name alternatives or state when not to use it, so it's not a perfect 5.

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