update_budget

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

Description adds details beyond annotations: 'echoing previous and new value', 'overwrites', 'applies immediately'. No contradiction; annotations indicate destructive, idempotent write.

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, each with distinct purpose: action, behavior, guidance. No redundant words, well front-loaded.

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 2-param tool with annotations, description covers purpose, behavior, and usage hint. Lacks output format details, but acceptable given no output schema.

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 covers 100% with descriptions. Description adds 'in USD' and implies output echo, not essential for parameter understanding. Baseline 3.

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?

Description clearly states 'Set an ad group's daily spend budget in USD' with verb and resource. It distinguishes from siblings like get_ad_group (read) and update_bid (different resource).

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?

Provides context: 'Budgets live on ad groups, not campaigns' and suggests reading first with get_ad_group. Does not explicitly list when not to use or alternatives, but guidance is clear.

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