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

The readOnlyHint annotation already establishes this is a safe read, so the description's main added value is telling the agent what each request returns (workspace_id, brand_id, channel_id, available_requests). It does not disclose limits on the discovery calls, error behavior for invalid report_names/actions, or the nullable/default semantics of optional params.

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?

Front-loaded with a one-line purpose followed by a scannable stepwise bullet list where every line maps to an invocation pattern. The three actions_details examples are somewhat redundant and the brand bullet reads as an afterthought, but nothing is padding.

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 6-parameter polymorphic discovery tool, the description supplies the sequencing, the request-mode routing, and the key return fields, and an output schema exists to cover response structure. The remaining gap is per-request required/optional rules and valid platform values, which an agent must infer from examples.

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 across 6 parameters, the description carries the full documentation burden and mostly does: it enumerates all three request enum values and shows platform, report_names, actions, brand_id and workspace_id in realistic example calls. It is weaker on which params are optional vs. required per request (only 'accounts' is explicitly noted as needing no extra params) and on accepted platform strings beyond the two examples.

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 concretely that this is a planning/setup helper for YouTube queries and breaks it into three discovery requests (accounts, actions_details, brands) with what each returns. An agent can tell it is the metadata/discovery precursor rather than a data-fetching tool, although it never names the sibling tools it precedes.

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?

Step 1 / Step 2 / Additional ordering gives an explicit call sequence, and each bullet shows the exact parameter combination that selects a given mode. It stops short of stating when to skip this tool or when to switch to execute_action/query_data.

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