fill_template

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

Beyond the annotations (which only mark non-readOnly, non-destructive), the description adds key behavioral context: it writes a NEW file, leaves input unchanged, and expands specific template constructs. This helps the agent understand side effects. It doesn't mention whether it can overwrite an existing output_path, but overall it adds meaningful behavior beyond 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 two sentences, front-loaded with the core verb and resource, then details output behavior and a recommended prerequisite. Every sentence contributes unique information, with no padding. It's concise and well-structured for quick scanning.

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 has an output schema (not detailed here) and rich annotations, the description covers the main functionality, output behavior, and a usage tip. It doesn't elaborate on options like dry_run or backup, but those are already in the schema. The description is sufficient for an agent to decide when and how to call it, though it could mention how it handles nested data structures more explicitly.

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?

Schema coverage is 100% (all parameters are described in the schema). The description adds value by specifying the default output_path behavior ('<template>_filled.<ext>'), which the schema does not mention. It also indirectly explains how data interacts with loops/conditions, though that's not parameter-specific. This raises the score above baseline from 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 fills placeholders in a template document, expanding loops and conditions, and writes a new file. It distinguishes itself from siblings like edit_office_document by explicitly noting it creates a new file and leaves the input unchanged. The verb 'fill' plus specific placeholder syntax and condition handling make 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 advises running validate_template first to catch missing keys early, providing a clear sequencing guideline. It does not explicitly mention when not to use this tool versus alternatives like edit_office_document or convert_document, but the 'new file' behavior implicitly contrasts with in-place modification. The guidance is adequate but lacks explicit alternatives and exclusions.

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