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

Beyond the annotations, the description explains important behaviors: create or replace semantics, mode-dependent defaults, mixed membership, expectedRevision as an update guard, and that existing content settings are preserved. This substantially clarifies the tool's side effects and complements the idempotentHint.

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 dense sentences, all of which earn their place. The core action is front-loaded, and the mode selection, update condition, and content-preservation guarantee follow without repetition or filler.

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?

Despite strong behavioral detail, the tool has 11 required parameters and no schema descriptions, and the description does not cover idempotency, asset/project relationships, or how to form a valid request. An agent would still struggle to populate most required fields 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?

With 0% schema description coverage, the description must carry parameter meaning, but it only elaborates on defaultCreationMode and expectedRevision. The other nine required parameters (idempotencyKey, asset IDs, workspaceId, captionThemeId, etc.) remain unexplained, leaving the agent without enough semantic grounding.

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 opens with 'Create or replace a Growth+ Series identity and defaults', which names the exact operation and resource. It clearly differentiates from siblings like series_assign or story_kits_apply by focusing on the Series identity/defaults object.

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 gives useful context for the create-vs-update distinction: updates require expectedRevision, and defaultCreationMode selects branding mode. However, it never states when to choose this tool over related siblings such as story_kits_apply or series_assign, so usage guidance is only implied.

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