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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint, so the safety profile is covered. The description adds useful behavioral context by specifying what the response will contain and by noting the data source for the command reference, going beyond the structured fields.

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 with no filler; the first sentence front-loads the tool's core behavior and output contents, and the second adds provenance concisely. Every clause 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?

For a simple read-only lookup tool, the description enumerates all meaningful output categories and the schema fully documents both parameters. No output schema exists, but the description compensates by stating what the agent will receive.

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 both 'command' and 'locale' are already documented with examples and enum values. The description's mention of 'parameters with types/ranges/options' describes the tool's output rather than adding per-parameter meaning, 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?

The description uses a specific verb ('Explain') and object ('a single ZPL command') and enumerates the concrete output: syntax, parameter types/ranges/options, a fragment example, and renderer support. This makes the tool's scope clear and distinguishes it from preview, validation, and broader explanation siblings.

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 single-command scoping implies when the tool should be used, but the description does not explicitly mention alternatives or state when not to use it. Given the existence of 'explain_zpl' among siblings, an explicit routing cue would have strengthened the guidance.

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