documents_by_tag

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

With no annotations, the description carries the full burden. It discloses that the output is paths (not content) and directs the user to read_knowledge for content, adding meaningful behavioral context. However, it does not mention error handling, case sensitivity, or explicitly state that it is a read-only operation beyond the listing verb.

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 sentences front-load the core purpose, then add usage context and return-value guidance without any fluff. Every sentence earns its place.

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?

The tool is simple (one parameter) and an output schema exists, so the description does not need to explain return values in detail. It covers purpose, usage, parameters, and even the next step (read_knowledge), making it complete for the tool's complexity.

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 has 0% description coverage, but the description explains the 'tag' parameter as a 'frontmatter tag' and gives examples, which is exactly what the schema lacks. It also connects the parameter to list_tags, effectively compensating for the schema gap.

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 a specific action 'List documents carrying a frontmatter tag' with concrete examples, clearly distinguishing it from siblings like list_tags and semantic_search. The verb+resource+condition structure makes the tool's purpose immediately obvious.

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 states the intended use case ('tag-based navigation') and provides an actionable prerequisite ('Call list_tags first if unsure which tags exist'). This gives the agent clear when-to-use guidance and points to an alternative tool, satisfying the highest bar.

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