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

Even with annotations already declaring readOnlyHint=true, idempotentHint=true, and destructiveHint=false, the description adds concrete behavioral details: compact-by-default output keyed by county with rows of {slug, name, verified}, approximate token size, and the existence of a detail mode. These shape and size tradeoffs go beyond what annotations provide.

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 efficient and front-loaded, leading with the core purpose and then layering output shape, size, and parameter behavior. It is slightly dense, with long clauses and parentheticals, but every phrase contributes useful information and nothing is redundant with the 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?

With a high-coverage schema and an output schema present, the description covers the essential selection and invocation concerns: what the tool returns, how large the response is, and which parameter mode to use for which need. Prose coverage of `county` and `verifiedOnly` is absent, but those are fully documented in the schema, so nothing critical 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?

The input schema already provides full parameter descriptions (100% coverage), so the baseline is 3. The description raises this by spelling out the fields in a full record ('department, fee-schedule URL, phone, code cycles, notes') and clarifying the compact output shape, which adds meaning beyond the schema's 'full record' phrasing. However, it doesn't add new semantic detail to `county` or `verifiedOnly`.

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 specific verb and object: 'List the jurisdictions in Kolmo's permit catalog (King, Pierce, Snohomish counties).' It clearly identifies the resource and scope, and goes further by naming downstream tools that consume its output (estimate_permit_fee, check_permit_requirements, get_permit_rule_details), which distinguishes its purpose from sibling tools.

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?

It explicitly states when to use this tool: 'enough to pick a jurisdictionSlug for estimate_permit_fee, check_permit_requirements or get_permit_rule_details.' It also provides intra-tool guidance, explaining when to use `slug` for one full record versus `detail: true` for all rows and noting that the full catalogue is compact (~4K tokens) with a much larger detail mode.

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