lookup_itemResolve an item name to Grand Exchange ID and latest price. Uses exact name match first, then wiki opensearch. Prefer this before get_item_price when you only know the name.
| Name | Required | Description | Default |
|---|---|---|---|
| limit | No | Max matches to return (default 5) | |
| query | Yes | Item name or partial name to search for |
| Name | Required | Description | Default |
|---|---|---|---|
| matches | Yes | Matching Grand Exchange items, best match first |
Changes observed during successful MCP inspections.
Output schema / (root)Previous value: -nullNew value: +{
+ "$schema": "https://json-schema.org/draft/2020-12/schema",
+ "additionalProperties": false,
+ "properties": {
+ "matches": {
+ "description": "Matching Grand Exchange items, best match first",
+ "items": {
+ "additionalProperties": false,
+ "properties": {
+ "error": {
+ "description": "Why this row could not be resolved",
+ "type": "string"
+ },
+ "id": {
+ "description": "Grand Exchange item ID",
+ "type": "integer"
+ },
+ "name": {
+ "description": "Item name",
+ "type": "string"
+ },
+ "price": {
+ "description": "Latest price in coins, when known",
+ "type": "number"
+ },
+ "timestamp": {
+ "description": "ISO timestamp of the price sample",
+ "type": "string"
+ },
+ "volume": {
+ "description": "Latest trade volume, when known",
+ "type": "number"
+ },
+ "wikiUrl": {
+ "description": "RuneScape Wiki page URL",
+ "type": "string"
+ }
+ },
+ "required": [
+ "id",
+ "name"
+ ],
+ "type": "object"
+ },
+ "type": "array"
+ }
+ },
+ "required": [
+ "matches"
+ ],
+ "type": "object"
+}Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Adds search strategy beyond annotations: exact name match first, then wiki opensearch fallback. Annotations already declare readOnly, idempotent, openWorld, and non-destructive behavior. It does not mention rate limits or failure modes, but provides useful beyond-schema behavior.
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 with zero wasted words. The core action is front-loaded, followed immediately by the search strategy and routing guidance.
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 lookup tool with rich annotations, full schema coverage, and an output schema, the description supplies the necessary purpose, search behavior, and sibling routing. No critical agent-facing context 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?
Schema description coverage is 100%, so both query and limit are already well documented in the schema. The description adds no parameter syntax, default, or constraint beyond what the schema provides. Baseline 3 is appropriate when schema does the heavy lifting.
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?
States a specific verb and resource: resolve an item name to Grand Exchange ID and latest price. It explicitly distinguishes itself from get_item_price by routing name-only lookups here. An agent can identify the tool's purpose without opening the schema.
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?
Gives an explicit routing rule: prefer this before get_item_price when you only know the name. This names an alternative and a condition, though it does not cover when-not cases or other siblings like browse_items. Clear context without full exclusion guidance.
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.