sa4_listAll Australian SA4s. Optional ?state= filter. Returns
{sa4, state} per row. Flat cost.
Price: 3¢ per call.
| Name | Required | Description | Default |
|---|---|---|---|
| state | No | Filter by state / territory. Optional — ~110 SA4s nationally. |
Changes observed during successful MCP inspections.
Output schema / (root)Previous value: -{
- "properties": {
- "available": {
- "anyOf": [
- {
- "type": "boolean"
- },
- {
- "type": "null"
- }
- ],
- "description": "`false` on no-data responses. Omitted on success — branch on `data !== null` if you want a single discriminator.",
- "title": "Available"
- },
- "data": {
- "anyOf": [
- {
- "items": {
- "description": "One row in the SA4 directory.",
- "example": {
- "sa4": "Newcastle and Lake Macquarie",
- "state": "NSW"
- },
- "properties": {
- "sa4": {
- "description": "SA4 name.",
- "title": "Sa4",
- "type": "string"
- },
- "state": {
- "description": "State / Territory abbreviation (NSW, VIC, ...).",
- "title": "State",
- "type": "string"
- }
- },
- "required": [
- "sa4",
- "state"
- ],
- "title": "Sa4ListItem",
- "type": "object"
- },
- "type": "array"
- },
- {
- "type": "null"
- }
- ],
- "description": "The endpoint's payload, or `null` when Microburbs has no value.",
- "title": "Data"
- },
- "message": {
- "anyOf": [
- {
- "type": "string"
- },
- {
- "type": "null"
- }
- ],
- "description": "Human-readable explanation. Omitted on success.",
- "title": "Message"
- },
- "reason": {
- "anyOf": [
- {
- "type": "string"
- },
- {
- "type": "null"
- }
- ],
- "description": "Machine-readable slug naming the no-data condition (e.g. `no_avm_for_GANSW704074813`). Stable per endpoint. Omitted on success.",
- "title": "Reason"
- }
- },
- "title": "ApiResponse[list[Sa4ListItem]]",
- "type": "object",
- "x-fastmcp-top-level-schema": "ApiResponse_list_Sa4ListItem__"
-}New value: +nullDoes the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, covering safety. The description adds valuable behavioral details: the return format '{sa4, state}' per row, the flat cost (3¢ per call), and the optional state filter. These go beyond annotations without contradiction.
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 two sentences plus a cost line, with no fluff. It front-loads the core purpose, then the filter, return format, and cost. Every sentence earns its place, making it easy to scan.
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 simple list tool with one optional parameter and no output schema, the description covers everything needed: what it does, the filter, the return shape, and cost. Annotations cover safety. Nothing essential is missing for an agent to call it correctly.
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% for the 'state' parameter, so the schema already documents it. The description adds the note '~110 SA4s nationally,' which provides a sense of scale but doesn't significantly enhance parameter semantics beyond what the schema offers. Baseline 3 is appropriate.
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 the tool's purpose: 'All Australian SA4s.' It specifies the resource (SA4s), the action (list), and the scope (all national SA4s). It distinguishes from siblings like sa4_profile by being a list operation, and from lga_list and suburbs_list by focusing on SA4s specifically.
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 provides clear context: it's for listing all SA4s, with an optional state filter. It doesn't explicitly mention alternatives or when-not-to-use, but the purpose is unambiguous. Given the many sibling tools, a brief pointer to when to use this vs sa4_profile would improve, but the current context is sufficient for an agent to decide.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Add one secure layer between your agents and this server.