google_ads_asset_group_assets_replace

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

With no annotations, the description takes full responsibility for behavioral disclosure. It details that the operation is atomic (all three steps in one mutate), creates a new asset, removes the old link without deleting the asset, is not reversible, and returns a specific structure. It also mentions the duplicate-link rejection behavior, providing comprehensive transparency about side effects and constraints.

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?

Although the description is longer than typical, every sentence delivers critical information: atomicity, the NOT_ENOUGH_* error context, old asset non-deletion, return format, irreversibility, and the prerequisite list call. No fluff or redundancy; it is efficiently front-loaded with the core action.

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 complex mutating tool with no annotations and no output schema, the description covers all necessary context: the atomic multi-step operation, the reason for atomicity (minimum asset count), the return structure, the irreversibility and rollback guidance, and the required precursor step. It is fully sufficient for an agent to understand and execute the tool correctly.

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% and every parameter has a description, but the tool description adds extra meaning beyond the schema: new_text's display-width limits and duplicate-text rejection, field_type's note that the same asset can be linked under multiple field types, and old_asset_id's validation rule. This enhances understanding beyond the basic schema definitions.

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 states a specific verb+resource: 'Swaps one headline, long headline or description of a Performance Max asset group for new text. Mutating.' It clearly identifies the operation and distinguishes it from sibling tools like google_ads_asset_group_images_replace (images vs. text) and google_ads_asset_group_assets_list (read vs. write).

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 instructs calling google_ads_asset_group_assets_list first to obtain old_asset_id, and explains that removing an asset on its own fails with NOT_ENOUGH_* errors, implying this replace tool is the correct approach to maintain minimum asset counts. It also advises recording before-state with mureo_state_action_log_append for rollback, giving clear context for when and how to use this tool.

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