text_diffCompute an exact line-based diff between two texts with add/remove/unchanged stats.
| Name | Required | Description | Default |
|---|---|---|---|
| modified | Yes | The text after the change | |
| original | Yes | The text before the change |
| Name | Required | Description | Default |
|---|---|---|---|
| lines | No | ||
| stats | No | ||
| result | No | The result, when it is not an object |
Changes observed during successful MCP inspections.
Input schema / $schemaRemoved value: -"https://json-schema.org/draft/2020-12/schema"Output schema / $schemaRemoved value: -"https://json-schema.org/draft/2020-12/schema"Input schema / properties / modified / descriptionAdded value: +"The text after the change"Input schema / properties / original / descriptionAdded value: +"The text before the change"Output schema / (root)Previous value: -nullNew value: +{
+ "$schema": "https://json-schema.org/draft/2020-12/schema",
+ "additionalProperties": {},
+ "properties": {
+ "lines": {
+ "items": {},
+ "type": "array"
+ },
+ "result": {
+ "description": "The result, when it is not an object"
+ },
+ "stats": {
+ "additionalProperties": {},
+ "properties": {
+ "added": {
+ "type": "number"
+ },
+ "removed": {
+ "type": "number"
+ },
+ "unchanged": {
+ "type": "number"
+ }
+ },
+ "type": "object"
+ }
+ },
+ "type": "object"
+}Input schema / properties / modified / descriptionRemoved value: -"The text after the change"Input schema / properties / original / descriptionRemoved value: -"The text before the change"Output schema / (root)Previous value: -{
- "$schema": "https://json-schema.org/draft/2020-12/schema",
- "additionalProperties": {},
- "properties": {
- "lines": {
- "items": {},
- "type": "array"
- },
- "result": {
- "description": "The result, when it is not an object"
- },
- "stats": {
- "additionalProperties": {},
- "properties": {
- "added": {
- "type": "number"
- },
- "removed": {
- "type": "number"
- },
- "unchanged": {
- "type": "number"
- }
- },
- "type": "object"
- }
- },
- "type": "object"
-}New value: +nullInput schema / properties / modified / descriptionAdded value: +"The text after the change"Input schema / properties / original / descriptionAdded value: +"The text before the change"Output schema / (root)Previous value: -nullNew value: +{
+ "$schema": "https://json-schema.org/draft/2020-12/schema",
+ "additionalProperties": {},
+ "properties": {
+ "lines": {
+ "items": {},
+ "type": "array"
+ },
+ "result": {
+ "description": "The result, when it is not an object"
+ },
+ "stats": {
+ "additionalProperties": {},
+ "properties": {
+ "added": {
+ "type": "number"
+ },
+ "removed": {
+ "type": "number"
+ },
+ "unchanged": {
+ "type": "number"
+ }
+ },
+ "type": "object"
+ }
+ },
+ "type": "object"
+}Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so safety and purity are covered. The description adds that the diff is exact and line-based and mentions output stats, which is modest value but says nothing about limits, ordering, or edge cases beyond what the schema/annotations carry.
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 sentence that front-loads the operation and tacks on the return stats. Every clause earns its place, with no filler or repetition of the name.
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, side-effect-free two-input utility with full schema coverage, complete annotations, and an output schema, the description needs to do little. Nothing an agent needs in order to invoke this correctly 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% with only two well-named string parameters, so the schema fully documents the inputs. The description's 'two texts' framing adds nothing beyond the schema, making 3 the correct baseline.
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+resource ('Compute an exact line-based diff') and the algorithm's scope plus the shape of what it returns (add/remove/unchanged stats). No sibling tool overlaps with diffing, and an agent can immediately tell what this does.
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 operation is self-evident enough that usage is implied (call it to diff two texts), but there is no explicit when-to-use statement, no exclusions, and no mention of alternatives among the siblings. Minimum viable 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.