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

With no annotations, the description carries the full burden, and it discloses the salient behaviors: it is a read/lookup returning the 'rule IR', it exposes a content hash, and asOf narrows to a single in-force version while omitting it returns all versions. No safety, authorization, or rate-limit notes are given, but for a read-only getter this is largely adequate.

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, front-loaded with the core verb+resource, with usage and the asOf nuance appended. The middle enumeration of return fields is dense but each item is informative; structure is efficient overall.

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?

There is no output schema, so the description usefully enumerates the return payload (citation, excerpt, window, formula, dependencies, hash) and explains versioning, which an agent needs to call it well. It leaves the discovery path (which sibling to use to obtain a ruleId) only partially signposted in the schema.

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 both parameters (ruleId, asOf) are already documented, including the asOf semantics that the description merely restates. The description adds no syntax or format detail for ruleId beyond the schema's example, so the baseline of 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?

The verb+resource is precise ('Get a tax rule in full') and the description enumerates the returned artifacts (citation, verbatim excerpt, validity window, formula/guard, dependencies, content hash), which clearly separates it from calculate_tax or lookup_tax_parameter. It does not, however, name any sibling tool explicitly to draw the boundary, so it lands at clear-but-undifferentiated.

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?

'Use to quote and explain the actual law behind an answer' gives a concrete usage context, and the asOf note adds a usage condition. There are no explicit exclusions or named alternatives (e.g., search_tax_rules for discovery), so it stops short of full when/when-not guidance.

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