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

Annotations already establish read-only, idempotent, non-destructive behavior, and the description adds genuinely new context: only summaries and key parameters are returned (full standard text never reproduced), C-grade entries are unverified leads, and the category taxonomy is the vendor's rather than the issuing body's. That caveat set is exactly the kind of trait annotations cannot express.

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 explicit Purpose/Guidelines/Limits/Ex sections, which is good structure, but the long parenthetical enumerations of standard designators (D8178 / D8466 / D8474 / D8632...) consume substantial space for limited selection value and make the description feel padded.

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 nine-parameter search tool with an output schema (so return shape need not be described), the description covers scope, filtering strategy, quality tiers, and content caveats. Minor gaps remain around pagination semantics and how region interacts with the enumerated taxonomy, but nothing critical for correct invocation 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 coverage is 100%, so the baseline is 3; the description goes beyond it by showing how filters combine and by supplying concrete filter values, including non-obvious Chinese enum strings ('测试标准'), plus the meaning of verified=true. It still doesn't explain limit/offset/response_format behavior, which the schema carries.

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?

Starts with a specific verb+resource ('search the rCB technology and standards library') and enumerates concrete coverage (ASTM D-series, Chinese standards, pyrolysis processes, post-treatment). It does not, however, distinguish itself from close siblings like get_tech or get_carbon_standards, so an agent cannot rule out the retrieval-style alternative from the description alone.

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 actionable context: combine keyword with category and region, use verified=true to restrict to text-backed entries, and provides three worked example calls. It stops short of stating when NOT to use it or which sibling to prefer for a single-entry lookup, so no explicit alternatives are named.

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