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

With no annotations provided, the description carries the full burden. It explains the deterministic vs fuzzy behavior, the return fields (matched rate, match score, source URL), and the public nature. However, it does not disclose edge cases like what happens if no match is found or rate limits, which would raise transparency further.

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?

The description is comprehensive but not overly verbose. It is front-loaded with the core action, then explains the two modes, usage guidance, sibling reference, and a caveat. Every sentence adds value, though it could be slightly more concise by merging some examples.

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?

Given the tool's complexity (3 parameters, no output schema, no annotations), the description adequately covers purpose, parameter usage, when to use, and return values. It explicitly mentions the return fields, which is sufficient without an output schema. Minor gaps like error handling prevent a perfect score.

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 baseline is 3. The description adds significant value by explaining the id format with examples, providing category examples, and stating that id overrides country/category. This context helps the agent understand parameter usage beyond the schema.

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 clearly states that the tool picks a single statutory tax-rate slab, either by exact id or fuzzy match by country and category. It provides examples of id format and category inputs, and explicitly distinguishes itself from the sibling tool list_tax_rates by specifying that the latter is for broader exploration.

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 description explicitly states when to use this tool ('when a user asks what slab does X fall into...') and when not to ('For broader exploration... use list_tax_rates'). It also includes a caveat that the tool provides public statutory reference only, guiding the agent away from customer data queries.

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