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

Annotations already cover safety (readOnly, idempotent, non-destructive) and closed-world scope, so the description focuses on the useful non-obvious behavior: it derives future due dates rather than returning stored data, accepts several date formats, and scopes the five-year life rule to UN/ADR plastic and composite IBCs. It doesn't say what happens on missing or unreadable input, which keeps it short of a 5.

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 computed outputs, with no filler. The parenthetical qualifiers make the second sentence dense but each phrase carries information.

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 an eight-parameter, no-required-field computation tool with no output schema, the description tells the agent what it returns (dates) and in what format. Behavior on incomplete or inconsistent inputs is the only meaningful omission.

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%, so the baseline would be 3, but the description adds real meaning: accepted date syntaxes (MM/YYYY, 'March 2024', YYYY-MM) that the schema omits, the made-or-mark alternative, and the tie between the 'regime' parameter and plastic/composite IBCs. It still doesn't clarify how insp, leak, repair, and bottle interact to select a due date.

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?

It names a specific verb ('Work out') and a precise set of computed results: next leakproofness test, 2.5-year and 5-year inspections, last fill month, and end of five-year life. That is far more concrete than the sibling 'decode_un_packaging_mark', which only reads a mark, so an agent can distinguish them without opening either 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?

It states an input precondition ('Needs made, or a mark it can read the month of manufacture from'), which guides the made-vs-mark choice. But it never says when to use this versus the sibling decode_un_packaging_mark tool, nor does it list exclusions or alternatives.

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