Disco

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

The annotation readOnlyHint=true already indicates a safe read operation, but the description adds valuable context by stating 'No authentication required' and specifying that it returns 'all available subscription tiers with credit allowances and pricing.' This enhances transparency beyond the annotation, though it doesn't detail rate limits or error behaviors.

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 description is front-loaded with the core purpose in the first sentence, followed by authentication and usage context in two additional sentences. Each sentence adds value without redundancy, making it efficient and well-structured for quick understanding.

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?

Given the tool's simplicity (0 parameters, read-only, with output schema), the description is complete. It covers purpose, authentication, usage guidance, and output content, which is sufficient for an AI agent to select and invoke this tool correctly without needing further explanation of return values due to the output schema.

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 input schema has 0 parameters with 100% coverage, so the schema fully documents the lack of inputs. The description doesn't need to add parameter details, but it implicitly confirms no inputs are required by focusing on the output, which is appropriate. A baseline of 4 is given as it compensates adequately for the zero-parameter case.

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 clearly states the verb 'List' and resource 'available Disco plans with pricing,' distinguishing it from siblings like discovery_purchase_credits or discovery_subscribe that involve transactions. It specifies the scope as 'all available subscription tiers with credit allowances and pricing,' making the purpose explicit and distinct.

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?

The description explicitly states 'Use this to help users choose a plan,' providing clear context for when to invoke this tool. It also mentions 'No authentication required,' which implicitly distinguishes it from tools like discovery_login or discovery_account that require authentication, offering guidance on alternatives.

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