diff_snapshotCompare a Ninova page's current state against a stored snapshot to detect changes, such as updated grades, deadlines, or announcements.
Compare the current state of a Ninova page against a previously stored snapshot.
| Name | Required | Description | Default |
|---|---|---|---|
| url | Yes | ||
| label | No | ||
| snapshot_path | No |
| Name | Required | Description | Default |
|---|---|---|---|
| result | Yes |
Changes observed during successful MCP inspections.
v1.2.1Output schema / additionalPropertiesRemoved value: -trueOutput schema / propertiesAdded value: +{
+ "result": {
+ "additionalProperties": true,
+ "title": "Result",
+ "type": "object"
+ }
+}Output schema / requiredAdded value: +[
+ "result"
+]Output schema / titlePrevious value: -"diff_snapshotDictOutput"New value: +"diff_snapshotOutput"v0.2.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false and openWorldHint=true, so the safety profile is covered. The description adds only the comparison-against-stored-state idea, which is already implied by the name and parameters; it says nothing about behavior when no snapshot exists or how diffs are presented.
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?
A single front-loaded sentence with no filler; the verb and both operands appear immediately. Nothing wasted.
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?
An output schema exists, so return values need no explanation, and the tool is read-only and single-purpose. However, the ambiguity over how the target snapshot is identified (label vs snapshot_path, and the failure mode when neither is valid) leaves a real operational hole for an agent.
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 0% for all three parameters, and the description does not compensate. It does not explain what url points at, what label means as a snapshot identifier, what snapshot_path is, or how label and snapshot_path interact (e.g., mutually exclusive selectors).
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 (compare) and both resources: the current page state and a previously stored snapshot. It is clear what the tool does, though it does not name its closest sibling snapshot_page, leaving the create-vs-compare relationship to inference.
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?
No statement of when to use this versus read_page or snapshot_page, and no prerequisites. The phrase 'previously stored snapshot' hints that a snapshot must exist first, but the description never says how it is created or what happens if it is absent.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.