[Feature Request]: Display default values from input_schema in test tool screen

[madhav165]

🧭 Type of Feature

Please select the most appropriate category:

• Enhancement to existing functionality
• New feature or capability
• New MCP-compliant server
• New component or integration
• Developer tooling or test improvement
• Packaging, automation and deployment (ex: pypi, docker, quay.io, kubernetes, terraform)
• Other (please describe below)

---

🧭 Epic

Title: Improved Usability in Tool Testing UI
Goal: Make testing tools easier and faster by pre-populating inputs with sensible defaults defined in the schema
Why now: Several tools already define default values in input_schema, but they are not surfaced in the Test Tool UI, leading to repetitive manual entry. This reduces developer friction, especially when testing frequently used tools during iteration.

---

🙋‍♂️ User Story 1

As a: Developer testing tool integrations
I want: The Test Tool UI to auto-populate fields with values from the input_schema.default
So that: I can test tools quickly without manually filling in common/default input values

✅ Acceptance Criteria

Scenario: Test Tool UI displays default values
  Given a tool with an input_schema that defines default values
  When I open the tool in the Test Tool UI
  Then the input fields are automatically pre-filled with those default values

Scenario: Default values are editable
  Given default values are pre-filled
  When I change them in the UI
  Then the modified values are used in the test request

---

🙋‍♂️ User Story 2

As a: Reviewer validating tool configuration
I want: To verify that default values from the input_schema are honored
So that: I can ensure tool schemas are correctly defined and useful in practice

✅ Acceptance Criteria

Scenario: Schema with invalid or missing defaults
  Given a schema where default is missing or incorrect
  When the Test Tool UI renders
  Then the corresponding input field remains empty or shows an error

---

📐 Design Sketch (optional)

flowchart TD
    A[Tool Input Schema] --> B[Parse default values]
    B --> C[Render Test Tool Form]
    C --> D[Pre-fill inputs with defaults]
    D --> E[User can edit values]
    E --> F[Send test request]

Loading

---

🔗 MCP Standards Check

• Change adheres to current [MCP specifications](https://developer.ibm.com/tutorials/awb-handle-remote-tool-calling-model-context-protocol/)
• No breaking changes to existing MCP-compliant integrations
• If deviations exist, please describe them below:

N/A

---

🔄 Alternatives Considered

• Manually entering default values each time → inefficient
• Hardcoded UI-side defaults → violates schema-driven design and not scalable
• Schema validation-only UI → doesn’t aid usability or accelerate testing

---

📓 Additional Context

• Related bug: Inputs with type: boolean are not rendering correctly in UI (related to schema interpretation)
• Suggested by multiple developers during integration testing
• Input schemas already support default values as per JSON Schema

---

Let me know if you'd like this copy in Markdown file or PR-ready format.

[kevalmahajan]

Completed and merged into main via PR #644