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

Annotations already establish readOnlyHint=true and openWorldHint=false, so the safety profile is covered. The description adds genuinely non-inferable behavioral context: this is a paid call costing 5 prepaid credits and requiring production billing, which an agent must know before invoking.

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, zero filler: the computational purpose comes first and the cost gate follows immediately. Nothing extraneous and nothing buried.

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 simple two-parameter read-only computation this is close to adequate, and the output is implied by 'expiration dates'. However, with 0% schema coverage and no output schema, the missing timestamp format and the exact returned value shape (single date vs. date plus policy metadata) leave gaps an agent could hit at call time.

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 0%, so the description must carry parameter meaning. It does map the two fields loosely (created_at = 'creation time', retention_days = 'TTL'), but it does not specify the accepted timestamp format or timezone, leaving real ambiguity for a string-typed date input.

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 ('Compute') and resource ('policy-based expiration dates') and names its inputs (creation time, TTL). It is clear enough to distinguish from plausibly adjacent siblings such as privi_expiry_window, but it never explicitly contrasts itself with any sibling.

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?

There is no guidance on when to pick this tool versus privi_expiry_window, privi_pro_data_freshness, or privi_retry_schedule, and no stated exclusions. The only usage-shaped information is a billing prerequisite, not a selection rule.

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