list_addon_services

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It describes the return format ('Returns a list of add-on services with their basic information') and implies read-only behavior through the 'list' action. However, it doesn't mention potential limitations like rate limits, authentication requirements, or pagination behavior. The description adds some context but leaves gaps in behavioral transparency.

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 appropriately sized with three sentences that each serve a purpose: stating the tool's purpose, providing usage guidance, and describing the return value. It's front-loaded with the core functionality. There's minimal waste, though the second sentence could potentially be integrated more smoothly.

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 simple listing tool with one parameter and no output schema, the description covers the basics: purpose, usage, and return format. However, with no annotations and no output schema, it could provide more context about authentication requirements, rate limits, or error conditions. The description is adequate but has clear gaps in completeness.

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 100% description coverage, with the single parameter 'json' fully documented in the schema. The description doesn't add any parameter information beyond what's already in the schema. According to the scoring rules, when schema_description_coverage is high (>80%), the baseline is 3 even with no param info in the description.

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 tool's purpose: 'List available Heroku add-on services' with the verb 'list' and resource 'add-on services'. It distinguishes from some siblings like 'create_addon' or 'get_addon_info' by focusing on listing all available services rather than creating or getting specific ones. However, it doesn't explicitly differentiate from 'list_addon_plans' which might list plans for specific services.

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 provides explicit guidance: 'Use this tool when you need to view all available add-on services.' This clearly indicates when to use it. However, it doesn't specify when NOT to use it or mention alternatives like 'list_addon_plans' for different listing needs, which would be helpful for sibling differentiation.

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