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

Goes well beyond the annotations by disclosing side-effect scope: keeps existing run history, does not spend credits or start a run, and returns a conflict error on duplicate saves. The 'newest 20' inclusion rule for run_project is a non-obvious behavioral detail that only the description supplies.

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?

Front-loaded with the core action and required params, then layered with downstream effects and edge cases. It is long but nearly every sentence carries distinct information; only the name-length and checkId-origin restatements are redundant with the schema.

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 2-param mutation with no output schema, the description covers the return value shape ('returns the scenario with the same id'), id reuse across list_scenarios/run_scenario, project-run inclusion, history retention, cost, and the duplicate-save failure mode. Nothing an agent needs is missing.

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%, so both params are already documented in the schema. The description restates the 1–255 name bound and the 'checkId returned by check' origin, adding little beyond the schema, so the baseline 3 applies.

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?

States a specific verb and resource: 'Save the check from check as a named scenario.' It names the upstream source (check) and downstream consumers (list_scenarios, run_scenario, run_project), so an agent can distinguish it from every sibling without opening a schema.

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?

Usage context is clear: this persists a check as a reusable scenario that later feeds run_scenario and project-wide runs. It even gives a precondition-style exclusion (conflict error when the check is already a scenario). It stops short of explicitly stating when NOT to save versus, say, running a check ad hoc.

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