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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is covered. The description adds genuinely useful context beyond that: the cost asymmetry between free lookup actions and billed execute, and the account-fan-out ('free like every read, max 20'). It says nothing, though, about what an execute call actually returns.

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?

The lead sentence front-loads the read-only nature and the dispatch pattern, and the category list is compact and scannable. No wasted prose, though the tool roster is long and could be partially replaced by the free list_tools action it advertises.

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 dispatcher with no output schema, the description supplies what an agent needs to route correctly: the action modes, free-vs-billed behavior, and the tool inventory. It is only slightly short on describing the shape of execute results or error behavior.

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 description coverage is 100%, so the schema already documents every parameter (action, accounts, arguments, tool_name) including the enum values. The description reinforces 'never guess a tool_name' and the free/paid split but adds no new parameter syntax or format detail, which is the expected baseline when the schema does the heavy lifting.

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 this is a read/tool-lookup dispatcher ('Reads and tool lookup for Diagnostics') and enumerates the concrete sub-tools it fronts (explain_error, validate_campaign_draft, etc.), so the agent understands it is a gateway, not a single operation. It does not, however, distinguish itself from dispatcher-like siblings such as search_tools or start_here.

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 clear routing guidance for the action enum – list_tools and get_tool_schema are 'free' while execute bills – and adds the practical rule 'never guess a tool_name.' It stops short of stating when to prefer this tool over adjacent discovery tools like search_tools.

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