existdb_lookup_function

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

No annotations are provided, so the description carries the full burden. It discloses the return content (full signature, parameter descriptions, return type, usage notes) and input flexibility (local, prefixed, or partial match). The read-only nature is implicit, and ambiguous partial-match behavior is not fully explained, but for a simple lookup tool this is adequate.

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?

Three concise sentences, each adding distinct information: purpose, return detail, and input formats. There is no redundancy, fluff, or unnecessary detail. The most important information is front-loaded.

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 no output schema and no annotations, the description covers the essential aspects: what the tool does, what it returns, and how to specify the function name. It does not mention error behavior or explain the optional namespace usage beyond the schema, but for a straightforward lookup operation this is sufficient.

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 schema already describes both parameters fully (100% coverage), giving a baseline of 3. The description adds value by explaining that the name can be a partial match and that the tool can return one or more functions, which goes beyond the schema's simple examples.

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 a specific verb ('Look up') and resource ('documentation for eXist-db / XQuery functions'), and distinguishes from sibling tools by focusing on name-based lookup. It also specifies accepted name forms (local, prefixed, partial), making the tool's 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 gives clear usage context: this tool is for looking up function documentation by name, with examples of accepted formats. However, it does not explicitly name alternatives like existdb_search_functions or state when not to use this tool, so it lacks explicit exclusions or when-not guidance.

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