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

Annotations already declare readOnlyHint, idempotentHint, and closed-world behavior, so safety is covered. The description adds genuinely new context by disclosing what each entry contains (API key dashboard URL and an optional public key guide), which is behavior beyond the annotations. It doesn't discuss ordering or stability of the list, keeping it from a 5.

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 short sentences with zero filler, front-loaded with the purpose before the return-content detail and the pointer to get_key_guide. Every sentence carries distinct information.

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?

With no output schema, the description properly compensates by naming the fields each entry returns and the conditional guide. For a zero-parameter read-only list tool this is nearly complete; only the notion of ordering or whether the set is static is unstated.

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 takes no parameters and the schema is an empty object, so there is no parameter meaning to add. Baseline 4 applies; there's no gap the description could have filled.

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?

Starts with a specific verb and resource ("List the LLM providers, gateways and web search services") and narrows the scope to BYOK-supported services, which cleanly separates it from siblings like list_models, list_projects, and list_chats. An agent can identify the resource without opening the schema.

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 routes follow-up behavior by naming the alternative: "Use get_key_guide to read a guide." That is a real when-to-use-next instruction rather than implied usage. It stops short of a full 5 because it doesn't state when to prefer list_providers over list_models or what a caller should do if a provider has no guide.

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