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

Annotations already declare readOnly, idempotent, non-destructive, closed-world behavior, so the bar is lower. The description contributes real behavioral context the annotations cannot: everyday wording is translated to clinical terminology before matching, prefix matching applies to code strings, and CPT text is absent for licensing reasons. It says nothing about how results are ranked or ordered, which is the remaining gap.

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 tightly packed sentences: the capability and match modes come first, then the usage trigger and the CPT exclusion. Every clause carries information; nothing is redundant with the title or schema.

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 three-parameter read-only search with no output schema, the description covers matching behavior, acceptable input phrasing, and scope limits well. The notable omissions are the shape of the returned results and the role of the system and limit parameters, which the low schema coverage leaves undocumented anywhere.

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 coverage is only 33%: query is documented in the schema, but limit and system are not. The description clarifies the query semantics (word match vs. code-prefix match) but never mentions the limit cap or what the icd10cm/hcpcs2 system selector does beyond naming the two code families in passing. Partial compensation only, so the baseline 3 fits.

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 and resource set (finds ICD-10-CM diagnosis codes and HCPCS Level II service/supply/drug codes) and defines the two match modes: official-description word match or code prefix match. It also carves out what is not covered (CPT 5-digit physician-service codes and why), so an agent can distinguish this from lookup_codes.

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?

Gives an explicit trigger: use when the statement prints a description but no code, or the code is partly illegible. It also states a clear exclusion (CPT not searchable), which prevents a wasted call. It stops short of naming the sibling lookup_codes as the exact-code alternative, so the routing is implied rather than spelled out.

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