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

Annotations already declare readOnlyHint, idempotentHint and non-destructive, so the safety profile is covered. The description adds real context beyond that: the sequence is contractual and day-by-day, each event carries its PSA section, and passing days_elapsed shifts the output from a full schedule to a triggered/pending split with days remaining.

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?

Two sentences, front-loaded with the scenario that activates the tool and then the mode-switching instruction. The middle clause stacks four enumerated events, making the first sentence dense, but no sentence is 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?

With no output schema, the description carries the burden of describing returns and does so: a day-by-day event sequence with PSA sections, plus triggered/next-event status when days_elapsed is given. What it leaves unstated is the concrete output shape (e.g., whether events come back as a dated list), which is a minor residual gap for a two-parameter reference tool.

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%, so the baseline is 3, but the description adds meaning the schema lacks: it explains that days_elapsed determines which events are already triggered and surfaces the next one with days remaining, which is return-shaping semantics rather than a restatement. The trigger parameter itself is only implied by 'after a missed monthly payment or a missed balloon,' relying on the schema for its enum values.

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 a specific resource (the CMBS special servicing timeline) and enumerates its contents: transfer to special servicer, SEC delinquency codes, appraisal reduction trigger, and the 120-day maturity window. Nothing in the sibling list (fee estimators, lender lookups, rate and underwriting tools) overlaps with this reference-sequence function, so the agent can route here without ambiguity.

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 states the triggering condition clearly (after a missed monthly payment or missed balloon) and explains the two modes of use: omit days_elapsed for the full sequence, supply it to get triggered events. It does not name sibling alternatives or exclusions, but the sibling set is functionally disjoint enough that this costs little.

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