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

Annotations already declare readOnly/idempotent/openWorld/destructive, so the safety profile is covered. The description adds genuinely useful behavioral context beyond that: the index is a nested tree with non-repeating indented sub-entries, matching happens in a small window of nearby lines, and it is keyless. This explains why long compound phrases fail — 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?

Front-loaded with the core action and payoff, then rationale, then the practical tip. It is on the verbose side with a long middle sentence, but nearly every clause carries information (examples, tree mechanics, routing).

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?

No output schema exists, yet the description explains what comes back (index entries with C.R.S. citations), how to consume it (pass to co_statute), and the keyless/auth posture. Nothing an agent needs to invoke it correctly is missing.

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 schema already documents both query and limit. The description reinforces query length (1-3 words) with rationale, but adds nothing about the limit parameter and no syntax beyond what the schema states. Baseline 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?

States a specific verb (search) and resource (Colorado Revised Statutes GENERAL INDEX) and clarifies scope with 'real subject-index search, not just a title list,' implicitly distinguishing it from the co_titles sibling. An agent can tell exactly what it returns — index entries with C.R.S. citations.

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?

Explains the workflow condition well: use it to map a plain-English topic to specific sections, then pass those to co_statute. It also gives query-shaping guidance (1-3 words). It stops short of explicit when-not-to-use rules (e.g., when to prefer co_titles over co_search), leaving that to inference.

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