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

Annotations already establish that this is a read-only, idempotent, non-destructive, closed-world lookup. The description adds meaningful domain behavior: it enumerates the five exit paths, notes that statutory price rules are site-published, and explains which dates are produced when a placed-in-service year is supplied. It stops short of describing output formatting or assumptions.

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 description is front-loaded and dense, naming the five paths first and then the date outputs. It is a single long sentence with some clause stacking, but nearly every phrase carries useful scope 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 a tool with rich schema descriptions, annotations, and no output schema, the description is substantially complete. It explains the domain outputs and the conditional date calculations, though it could clarify the response form or how extended_use_end_year changes results.

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?

All three parameters have complete schema descriptions, so the schema already carries parameter meaning. The tool description only adds that placed_in_service_year drives the date calculations; it does not elaborate on credits_start_next_year or extended_use_end_year beyond the schema.

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 resource and scope: the five Year 15 exit paths plus date calculations derived from a placed-in-service year. It is clear what the tool returns, but it does not explicitly distinguish itself from siblings like year15_summary or find_year15_properties.

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?

The description implies usage by saying dates are returned 'given a placed-in-service year,' and the schema notes that the year may be omitted for exit paths only. It does not explicitly say when to use this tool versus the sibling summary/search tools or state exclusions.

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