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

No annotations are provided, so the description must carry the full burden of transparency. It does so by disclosing that each entry includes an effective-from date and authoritative source URL, that agents should verify rates before quoting, and that the data is a 'public statutory reference' (contrasting with an authenticated tool). It omits potential edge-case behaviors like pagination or error handling, but the essential behavioral context is well covered.

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 dense but well-structured: the first sentence lists all jurisdictions and rates, followed by filter guidance, data provenance, usage examples, and an alternative tool. Every sentence adds value, though the first sentence is extremely long. It is front-loaded with the core action and purpose, making it easy for an agent to quickly grasp what the tool does.

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 no output schema, the description compensates by specifying what each entry contains (rate, effective-from date, source URL). It covers all relevant jurisdictions and tax types, explains filtering options, provides example queries, and distinguishes this public-reference tool from an org-specific one. This is sufficient for an agent to select and invoke the tool correctly across diverse user requests.

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 baseline is 3. The description adds meaningful value by expanding the enum values with concrete examples (e.g., 'IN GST (5/12/18/28...)', 'UK VAT (20 / 5 / zero / exempt)') and by showing how the filters map to user queries. It also clarifies the meaning of 'state-summary' and 'input-taxed' through context, going beyond the schema's brief descriptions.

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 opens with a clear verb and resource: 'List statutory tax-rate slabs by jurisdiction.' It enumerates specific jurisdictions and rate details, making the tool's scope unmistakable. Although sibling 'lookup_tax_rate' exists, the 'list' vs 'lookup' distinction is implicit and further reinforced by the exhaustive listing of slabs rather than a single rate lookup.

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 the tool: 'Use this when a user asks "what is the GST rate on X?"...' and provides a clear exclusion: 'for an org-specific tax assignment use the authenticated books_classify_event tool.' It also instructs agents to 'confirm the rate against the source before quoting figures,' adding a practical usage guideline. No ambiguity about when to choose this tool over alternatives.

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