list_gtm_accounts

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

Annotations already provide readOnlyHint=true and destructiveHint=false. The description adds valuable context: the tool lists only accounts the service account can read, is for first-time discovery, and explains the meaning of an empty list. It does not contradict the annotations. Additional details like rate limits or pagination are not needed for this simple list operation.

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, front-loaded with purpose, followed by usage guidance, then empty-result explanation. Every sentence adds value with no redundancy or unnecessary words.

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 for this simple list operation: it explains what it does (list accounts), when to use it (before audit_event_coverage), and what an empty result means. The tool has an output schema to describe return values, so no further detail is needed.

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 tool has zero parameters and 100% schema coverage (since schema is empty). Baseline is 4 for zero-parameter tools. The description does not need to add parameter semantics as there are none.

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 'List all GTM accounts the AdLoop service account / OAuth user can read.' It specifies the verb (list) and resource (GTM accounts), and distinguishes from sibling tools like list_accounts (which likely lists Google Ads accounts) and list_gtm_containers (which lists containers within an account).

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?

Explicitly directs the agent to use this tool 'for first-time discovery before calling audit_event_coverage — you need the account_id from here.' It also provides guidance on empty results, indicating the service account lacks read permission. This clearly tells when and why to use the tool.

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