build_prompt

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

With no annotations, the description carries full burden. It discloses 'No network request is made' and 'idempotent re-cleaning,' which are useful behavioral details beyond the tool name. However, it does not describe the output format or any potential failure modes, so it is not maximally transparent.

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 concise and well-structured: the first sentence states the purpose, the second gives the use case, and the final block explains the input format with examples. Every sentence adds value, and it is appropriately front-loaded with the core need-to-know 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?

Given the tool's complexity (13 parameters, no output schema, no annotations), the description provides enough to invoke it correctly for the main use case: cleaning an existing tag list. However, it leaves many optional parameters unexplained and does not describe the return value or expected output format, making it incomplete for a full understanding.

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 description extensively documents the `tag_string` parameter with format examples, which is critical since schema coverage is 0%. However, it does not explain the other 12 parameters (e.g., `background_mode`, `resolve_conflicts`), leaving their semantics largely to inference from names and defaults. The coverage is insufficient for a low-coverage schema.

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: 'Clean an already-known set of booru tags into a ready-to-use prompt.' It also distinguishes from siblings by specifying when to use it (when you already have a tag list) and referencing related tools like `search_posts` and `autocomplete_tags`.

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?

Explicit usage guidance is provided: 'Use this when you already have a tag list... and only want the cleaned output.' It also gives a clear exclusion: 'Do NOT pass natural-language sentences... use `autocomplete_tags` to find the canonical form.' This directly tells the agent when to use this tool vs. alternatives.

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