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

Annotations already declare readOnly/idempotent/non-destructive/openWorld=false, so the safety profile is covered. The description adds genuinely new behavioral context beyond the schema by naming the amortization method (straight-line), which is the key assumption an agent must know and is not present anywhere in the structured fields.

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 first sentence is well-front-loaded and dense with signal. The second sentence is a promotional pointer to an external 'full version' that does not help an agent select or invoke the tool and arguably implies the exposed tool is incomplete.

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?

With three trivial numeric inputs, full schema coverage, and annotations handling the safety profile, the main remaining need is what the tool returns — and the description covers that (recognized-to-date vs. remaining liability) despite no output schema. Only the vague 'full version' link leaves residual ambiguity.

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% with all three required numeric parameters documented, so the baseline is 3. The description restates the concept of an upfront payment and contract term but adds no units, ranges, or edge-case handling beyond what the schema already provides.

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 states a specific verb and resource ('Straight-line an upfront payment across the contract term') plus the exact output it produces ('revenue recognized to date versus the remaining deferred-revenue liability'). This is precise enough to distinguish it from neighbors like mrr_bridge_planner or net_revenue_retention_forecaster without opening any 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 is only implied by the domain ('deferred revenue', 'contract term') rather than stated. There is no explicit when-to-use, no prerequisites, and no reference to sibling calculators, so an agent must infer applicability from the purpose sentence alone.

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