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

Annotations already declare readOnlyHint=true and openWorldHint=false, so safety is covered; the description usefully adds that the result is TypeScript signatures including cost information and promise-returning semantics. It omits what happens for unknown or invalid call names and does not mention any batching limit, so the added context is real but partial.

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 short sentences with no padding, but the lead sentence is tangled enough that the reader must re-parse it to extract the actual purpose. The trailing note about promises is front-loaded poorly, arriving after the less important detail about costs.

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, so the description carries the burden of describing the return value; it does state TypeScript signatures with per-call behavior and cost, which is adequate. It leaves gaps around error handling for bad names and the max-30 batching constraint, which matter for a reference-lookup tool.

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% and the single names parameter is documented in-schema with an example ('discord.getGuildMember'), so the baseline of 3 applies. The description's phrase 'the parameters of the one object it takes' describes the returned signature, not the input array, so it adds no input-side meaning.

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 conveys that this retrieves reference material for the calls a Run JavaScript block can make, plus what each does, its cost, and its single-object parameter shape. However, the phrasing 'Gets calls the code of a Run JavaScript block can make' is grammatically broken, and nothing distinguishes it from the sibling search_code_calls, so the agent has to infer which is the lookup-by-name tool.

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?

There is no explicit when-to-use guidance and no mention of the obvious alternative, search_code_calls, which sits right next to it in the sibling list. The agent is left to infer that this is the batch-by-name variant from the schema's names array alone.

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