formats

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

Since no annotations are provided, the description carries the full burden. It discloses the MODE ('mixed (read + write)'), AUTH ('OAuth 2.0 required'), CREDITS ('Reads = 0. Writes = 0 credits (config changes only)'), and OUTPUT structure. It also details the behavioral traits of each sub-operation, including which are read-only, write, or destructive, and the implications of destructive actions (e.g., 'delete_recipe: Destructive write — does not affect existing creatives').

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 well-structured with clear sections (MODE, AUTH, CREDITS, OUTPUT, WHEN TO USE). It is front-loaded with the purpose. While it is somewhat long, every sentence adds value, and the bullet points for action types improve readability. However, some repetition of schema content could be trimmed.

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 description is complete given the tool's complexity and lack of output schema. It explains the output fields (id, name, dimensions, creative_type, applicable_sites), covers authentication, credits, and sub-operations. It provides enough context for an AI agent to understand when and how to use this tool. The differentiation from siblings adds to completeness.

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 has 100% description coverage, so the baseline is 3. The description repeats some parameter details (e.g., action enum values) but does not add significant new meaning beyond the schema's descriptions. The schema already explains each action in detail. The description provides a high-level overview but does not significantly enhance parameter understanding.

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 purpose: 'Manage the Custom Format Registry — reusable creative format recipes with multi-site scope.' It uses a specific verb 'manage' and identifies the resource as creative format recipes. It also distinguishes itself from sibling tools like 'blueprint' and 'creative_assets', providing clear differentiation.

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 explicitly states when to use the tool: 'Use formats to define reusable creative format specifications' that can be applied across multiple GAM networks. It also provides explicit scenarios to avoid by stating what it is NOT the same as (blueprint and creative_assets). The 'WHEN TO USE' section provides clear guidance.

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