scenario

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

With no annotations, the description carries the full burden and does add real signal: save has a filesystem side effect at scenarios/<id>.json and performs contract checking, while validate reports every blocking problem including corpus fragments not visible on the calculation day. However, list and get are completely undocumented, and there is no mention of overwrite semantics, permissions, or whether save is destructive.

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 action list is front-loaded in the first sentence, which is the right structure for a multiplexed tool. The second sentence is long and clause-heavy ('including corpus fragments not visible on the calculation day when the index exists') but the content is substantive rather than filler.

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?

An output schema exists, so return values need not be described. Still, for a four-action tool with zero schema description coverage, the description omits the per-action parameter mapping and never says what list or get do, leaving meaningful gaps an agent must guess at.

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 0% and 'action' is a bare string, so enumerating the four valid action values is genuinely necessary and the description supplies it. But 'spec' is never explained anywhere and 'id' is only implied through the file path pattern; which parameters apply to which action is left to inference.

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 names the resource (stored scenarios) and enumerates the four concrete actions (list, get, save, validate), so an agent knows what the tool manipulates. It does not differentiate itself from siblings like 'series', 'portfolio' or 'model', which likely also deal with persisted objects, so an agent cannot route purely on purpose text.

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?

It implicitly distinguishes save (writes a file after checking the contract) from validate (diagnoses why a scenario cannot be computed), which is a useful internal alternative. But there is no statement of when to use this tool instead of 'series', 'run' or 'portfolio', and no prerequisites or when-not conditions.

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