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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, openWorld), so the bar is lower. The description adds genuinely non-obvious behavior: a ZIP can map to multiple TDSPs, all matches are returned, and the agent must surface all rather than pick one — a result-cardinality trait not derivable from 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?

Two sentences, zero filler, and the core resolution behavior is front-loaded before the multi-match caveat. 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?

With no output schema, the description carries return-value burden, and it does explain that the electric utility (and Texas TDSP) matches are returned. It does not specify any other fields in the response, but for a single-parameter resolver this is nearly complete.

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% with one parameter, so the schema already documents the 5-digit format and example. The description's mention of '5-digit US ZIP' restates rather than extends the schema, so baseline 3 applies.

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?

Names a specific verb (resolve) and resource (ZIP code → electric utility/TDSP) with clear scope, including the Texas-specific TDSP concept. The purpose is unmistakably distinct from siblings get_ptc_rates and search_plans, which deal with rates and plan search rather than geographic utility resolution.

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 use case (have a ZIP, need the serving utility) is implied clearly, but the description never states when to reach for this versus the sibling tools or any prerequisite ordering. The multi-match instruction is behavioral guidance for handling results, not tool-selection guidance.

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