umbra_glossary

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

Beyond the annotations (readOnly, non-destructive, closed-world), the description reveals that the tool is 'deterministic local' and 'makes no model call and sends no data anywhere,' adding privacy guarantees. It also commits to 'never guessed' for unknown terms, setting accuracy expectations.

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, each earning its place: the function, the usage trigger, and behavioral safeguards. No redundant phrasing.

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?

For a simple one-parameter glossary tool with no output schema, the description covers the two operation modes, usage scenario, and behavioral guarantees. It is complete enough for an agent to select and invoke correctly.

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 describes the optional `term` parameter and its default listing behavior (100% coverage), so the baseline is 3. The description adds context that the term is 'precise, non-standard' and that unknown terms are handled plainly, enhancing the semantics.

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 opens with 'Return Umbra's authoritative fixed definition for one precise, non-standard Umbra term, or list all defined terms with short glosses,' which clearly identifies the verb and resource. It also distinguishes itself from sibling tools (audit, verify, write) by focusing exclusively on term definitions.

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?

It explicitly instructs 'Use this whenever a user asks what an Umbra term means,' providing a clear trigger. It does not explicitly name alternative tools or when not to use it, but the context is unambiguous given the sibling tools' distinct purposes.

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