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

Annotations already provide readOnlyHint=true and openWorldHint=true, so the bar for description is lower. The description adds value by explicitly stating this is a 'public, read-only lookup' and explaining it expands a list entry, which is helpful behavioral context beyond what annotations convey.

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 extremely concise with two sentences, no redundant words. The key information (verb, resource, parameter, usage context) is front-loaded in the first sentence, making it efficient for an AI agent to parse.

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 simplicity (1 parameter, no output schema, annotations cover safety), the description is complete. It clearly states the purpose, what the tool does, and when to use it relative to other tools. No additional information is needed for correct invocation.

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 coverage is 100% (single parameter fully described). The description simply restates that the parameter is a 'scenario slug or UUID', adding no new semantic information beyond what the schema already provides. Baseline score of 3 is appropriate.

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 uses a specific verb ('Return') and identifies the exact resource ('configuration and market-universe metadata') and parameter type ('scenario slug or UUID'). It also distinguishes from the sibling tool list_scenarios by mentioning that it expands an entry, making its purpose clear 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 states the tool is 'used before start_run' and notes it is a 'lookup that expands an entry from list_scenarios', providing clear context for when to invoke it. However, it does not explicitly mention when not to use it or describe alternatives, leaving some gaps.

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