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

Annotations already declare destructiveHint=true, but the description goes well beyond by explaining that the fold is irreversible, per-day detail is lost for good, analytics depends on those records, and session boundaries are server-decided rather than client-trusted. It provides rich context about side effects, default behavior, and operational constraints without contradicting the annotations.

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 critical 'PARTIAL SAVE' scope and irreversible WARNING are front-loaded, and the length is justified by the destructive, analytics-coupled behavior. Some sentences duplicate schema text and the paragraph is dense, but every sentence earns its place.

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 full burden and succeeds: it explains mutation scope, irreversibility, analytics coupling, session semantics, and default posture. An agent has everything needed to decide and safely invoke this destructive save.

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% and each nested field is fully described in the input schema, including defaults, warnings, and consequences. The description largely repeats that same field-level information, adding only the blanket instruction to leave fields null, so the baseline of 3 is appropriate.

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 with precise scope: writes ONLY the 'Usage' field while leaving other v1/v2 fields untouched. This distinguishes it from broader save_* siblings such as save_title_data and clearly communicates exactly what is being saved.

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?

Provides a clear default posture ('leave every field null unless you have a specific reason') and warns against lowering DailyWindowDays without adjusting the analytics cap. However, it does not name the read-only sibling get_usage or explicitly compare itself to save_title_data, so routing remains implied rather than explicitly stated.

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