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

Annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=true, so the safety profile is covered structurally. The description reinforces that it re-runs against live 'today's data' (consistent with the non-idempotent hint) and enumerates what it inspects, but adds no auth, rate-limit, or result-stability detail beyond that.

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?

One well-formed sentence that front-loads the action ('Re-run a saved purchase plan') and then the purpose and outputs. No 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 explained; the description still signals the kinds of changes reported. For a single-param read-only recheck it is essentially complete, with only minor room for stating prerequisites like plan freshness.

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?

With one parameter at 100% schema coverage, the schema already documents plan_id and its provenance from validate_purchase_plan. The description contributes nothing further about the identifier's format or constraints, 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?

The description gives a specific verb and resource ('Re-run a saved purchase plan against today's data') plus the observable outcomes (decisions, product records, receipt status). It clearly differs from validate_purchase_plan (which issues a plan) and fix_purchase_plan, though it never names a sibling explicitly.

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?

'before ordering' establishes the timing context in which this tool applies, and the schema ties plan_id back to validate_purchase_plan, implying the upstream step. There is no explicit when-not or named alternative, so it stops short of a 5.

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