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

Annotations already cover read-only/idempotent/open-world, but the description adds real context: refresh=True triggers a live re-check of the tier with Google (relevant to the open-world hint), and account selection can be overridden via a header.

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?

Two compact sentences, front-loaded with the resource and the return shape, then the flag behavior and header hint. No filler, though the header sentence is slightly tangential to the listing action itself.

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?

No output schema exists, and the description adequately describes the return (accounts with tiers). For a single-optional-param read tool with annotations covering safety, this is nearly complete; a note on ordering or empty results would be the only gap.

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?

Only one parameter with 0% schema description coverage, so the description must compensate, and it does: 'refresh=True re-checks the tier with Google' explains both the meaning and the side effect of the flag; the default of false is left to the schema. The X-Account-Email guidance also clarifies how callers target an account.

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?

Names a specific verb and resource ('List the Google accounts you connected for the LLM relay') plus the returned attribute (tier Free/Pro/Ultra), which distinguishes it from siblings like list_available_llm and list_models.

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?

Explains the refresh flag's purpose, states the model is chosen per request, and tells the agent how to pin a specific account via the X-Account-Email header. It does not explicitly say when to prefer this over list_available_llm, so it stops short of full alternative routing.

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