Inspector V2 UX - Handlers & Patterns
July 2, 2026 ยท View on GitHub
Brief | V1 Problems | V2 Scope | V2 Tech Stack | V2 UX | V2 Auth | V2 New Spec Impact
Overview | Features | Handlers | Screenshots | Components | Interfaces
Table of Contents
Client Feature Handlers
These are modals/panels that appear when the server invokes client capabilities.
Sampling Panel
Sampling requests appear in two contexts:
- Inline - When triggered during tool execution (shown in Tools screen)
- Modal - For standalone testing or when triggered outside tool context
Inline Expansion (Primary)
When a tool call triggers a sampling request, it appears inline within the tool execution flow:
+-------------------------------------------------------------------------+
| Tool: query_database [Executing...] |
+-------------------------------------------------------------------------+
| Parameters: { "table": "users", "limit": 10 } |
+-------------------------------------------------------------------------+
| [!] Sampling Request [Profile: Quick Mock v] |
| |
| +---------------------------------------------------------------------+ |
| | Model hints: claude-3-sonnet, gpt-4 | |
| | Messages: "Analyze this database schema and recommend an index..." | |
| | [View Details] | |
| +---------------------------------------------------------------------+ |
| |
| Response: |
| +---------------------------------------------------------------------+ |
| | Based on the query patterns, I recommend creating a composite | |
| | index on (user_id, created_at) for optimal performance... | |
| +---------------------------------------------------------------------+ |
| |
| Model Used: [mock-model-1.0] Stop Reason: [end_turn v] |
| |
| [Auto-respond] [Edit & Send] [Reject] |
+-------------------------------------------------------------------------+
Inline Features:
- Compact view showing essential info (model hints, message preview)
- [View Details] expands to show full request (like modal view)
- Testing Profile dropdown to quickly switch response behavior
- [Auto-respond] uses active Testing Profile to generate response
- [Edit & Send] allows modifying response before sending
- [Reject] declines the sampling request
- Response field pre-filled based on active Testing Profile
Modal View (Standalone Testing)
For testing sampling outside of tool execution, or when [View Details] is clicked:
+-------------------------------------------------------------------------+
| Sampling Request [x] |
+-------------------------------------------------------------------------+
| |
| The server is requesting an LLM completion. |
| |
| Messages: |
| +---------------------------------------------------------------------+ |
| | [0] role: user | |
| | "Analyze this data and provide insights about the trends..." | |
| | | |
| | [1] role: user | |
| | [Image: data_chart.png - Click to preview] | |
| +---------------------------------------------------------------------+ |
| |
| Model Preferences: |
| +---------------------------------------------------------------------+ |
| | Hints: ["claude-3-sonnet", "gpt-4"] | |
| | Cost Priority: low (0.2) | |
| | Speed Priority: medium (0.5) | |
| | Intelligence Priority: high (0.8) | |
| +---------------------------------------------------------------------+ |
| |
| Parameters: |
| Max Tokens: 1000 |
| Stop Sequences: ["\n\n", "END"] |
| Temperature: (not specified) |
| |
| Include Context: [x] thisServer |
| |
| ----------------------------------------------------------------------- |
| |
| Testing Profile: [Quick Mock v] [Edit Profiles] |
| |
| Response: |
| +---------------------------------------------------------------------+ |
| | Based on the data chart, I can see several key trends: | |
| | | |
| | 1. Revenue has increased 25% quarter-over-quarter | |
| | 2. User engagement peaks on Tuesdays... | |
| | | |
| +---------------------------------------------------------------------+ |
| |
| Model Used: [mock-model-1.0] Stop Reason: [end_turn v] |
| |
| [Auto-respond] [Reject Request] [Send Response] |
+-------------------------------------------------------------------------+
Modal Features:
- Display full sampling request details:
- Messages with text, image, and audio content
- Model hints and preferences (cost, speed, intelligence priorities)
- Max tokens, stop sequences, temperature
- Context inclusion settings
- Tools and toolChoice (if provided) for tool-enabled sampling
- Testing Profile selector with [Edit Profiles] link
- [Auto-respond] generates response from active profile
- Editable response field for mock LLM testing
- Model and stop reason fields for response
- Approve/Reject with human-in-the-loop
- Image/audio preview in messages
- Integration with Testing Profiles (see below)
Sampling with Tool Calling (2025-11-25)
Sampling requests can include tools and toolChoice parameters, enabling multi-turn agentic loops where the LLM can request tool execution.
Request with Tools:
+-------------------------------------------------------------------------+
| Sampling Request (with tools) [x] |
+-------------------------------------------------------------------------+
| |
| Messages: |
| +---------------------------------------------------------------------+ |
| | [0] role: user | |
| | "What's the weather in Paris and London?" | |
| +---------------------------------------------------------------------+ |
| |
| Available Tools (2): |
| +---------------------------------------------------------------------+ |
| | get_weather | |
| | Get current weather for a city | |
| | Parameters: { city: string } | |
| +---------------------------------------------------------------------+ |
| | get_forecast | |
| | Get 5-day forecast for a city | |
| | Parameters: { city: string, days: number } | |
| +---------------------------------------------------------------------+ |
| |
| Tool Choice: [auto v] (auto | none | required | specific tool) |
| |
+-------------------------------------------------------------------------+
Response with Tool Use:
When the LLM wants to call tools, the response includes stopReason: "toolUse":
+-------------------------------------------------------------------------+
| Sampling Response |
+-------------------------------------------------------------------------+
| |
| Response Content: |
| +---------------------------------------------------------------------+ |
| | I'll check the weather for both cities. | |
| +---------------------------------------------------------------------+ |
| |
| Tool Calls Requested: |
| +---------------------------------------------------------------------+ |
| | [1] get_weather({ "city": "Paris" }) | |
| | [2] get_weather({ "city": "London" }) | |
| +---------------------------------------------------------------------+ |
| |
| Model Used: [claude-3-sonnet] Stop Reason: [toolUse] |
| |
| [!] Server must execute tools and send follow-up sampling request |
| |
| [Reject Request] [Send Response] |
+-------------------------------------------------------------------------+
Multi-Turn Tool Loop Flow:
Server Client (Inspector)
| |
| sampling/createMessage (with tools) |
|--------------------------------------->|
| | [User reviews request]
| | [User approves/provides response]
| Response (stopReason: toolUse) |
|<---------------------------------------|
| |
| [Server executes requested tools] |
| |
| sampling/createMessage |
| (history + tool_results + tools) |
|--------------------------------------->|
| | [User reviews continuation]
| Response (stopReason: endTurn) |
|<---------------------------------------|
| |
| [Server processes final response] |
Tool Results in Follow-up Request:
The server sends tool results back in a continuation request:
+-------------------------------------------------------------------------+
| Sampling Request (continuation with tool results) [x] |
+-------------------------------------------------------------------------+
| |
| Messages: |
| +---------------------------------------------------------------------+ |
| | [0] role: user | |
| | "What's the weather in Paris and London?" | |
| | | |
| | [1] role: assistant | |
| | "I'll check the weather for both cities." | |
| | Tool calls: get_weather(Paris), get_weather(London) | |
| | | |
| | [2] role: user (tool_result) | |
| | get_weather(Paris): { "temp": 18, "conditions": "Sunny" } | |
| | get_weather(London): { "temp": 14, "conditions": "Cloudy" } | |
| +---------------------------------------------------------------------+ |
| |
| Available Tools (2): [same as before] |
| |
+-------------------------------------------------------------------------+
History View:
The History screen shows the complete tool loop as a nested chain:
[>] 14:35:22 tools/call weather_report [success] 2.5s [Replay]
+-- 14:35:23 sampling/createMessage (with tools) [+100ms]
| Response: toolUse - get_weather(Paris), get_weather(London)
+-- 14:35:24 [tool execution: get_weather x2] [+500ms]
+-- 14:35:25 sampling/createMessage (continuation) [+1.2s]
| Response: "Paris is 18C and sunny, London is 14C and cloudy"
Elicitation Handler
Elicitation requests appear in two contexts:
- Inline - When triggered during tool execution (shown in Tools screen)
- Modal - For standalone testing or when triggered outside tool context
Inline Expansion (Form Mode)
When a tool call triggers a form elicitation, it appears inline:
+-------------------------------------------------------------------------+
| Tool: process_data [Executing...] |
+-------------------------------------------------------------------------+
| Parameters: { "dataset": "quarterly_sales" } |
+-------------------------------------------------------------------------+
| [!] Elicitation Request (form) |
| |
| "Please confirm the data processing parameters." |
| |
| +---------------------------------------------------------------------+ |
| | include_deleted: [ ] No output_format: [CSV v] | |
| | date_range: [2024-01-01] to [2024-12-31] | |
| +---------------------------------------------------------------------+ |
| |
| WARNING: Server "data-processor" is requesting this data. |
| |
| [Cancel] [Submit] |
+-------------------------------------------------------------------------+
Inline Expansion (URL Mode)
When a tool call triggers a URL elicitation:
+-------------------------------------------------------------------------+
| Tool: connect_oauth [Executing...] |
+-------------------------------------------------------------------------+
| Parameters: { "provider": "github" } |
+-------------------------------------------------------------------------+
| [!] Elicitation Request (external URL) |
| |
| "Please complete OAuth authorization." |
| |
| URL: https://github.com/login/oauth/authorize?... [Copy] [Open] |
| |
| Status: Waiting for completion... (spinning) |
| |
| [Cancel] |
+-------------------------------------------------------------------------+
Modal View - Form Mode
For standalone testing or expanded view:
+-------------------------------------------------------------------------+
| Server Request: User Input Required [x] |
+-------------------------------------------------------------------------+
| |
| "Please provide your database connection details to proceed." |
| |
| ----------------------------------------------------------------------- |
| |
| Host * |
| +---------------------------------------------------------------------+ |
| | localhost | |
| +---------------------------------------------------------------------+ |
| |
| Port * |
| +---------------------------------------------------------------------+ |
| | 5432 | |
| +---------------------------------------------------------------------+ |
| |
| Database |
| +---------------------------------------------------------------------+ |
| | myapp_production | |
| +---------------------------------------------------------------------+ |
| |
| SSL Mode |
| +---------------------------------------------------------------------+ |
| | require v | |
| +---------------------------------------------------------------------+ |
| |
| WARNING: Only provide information you trust this server with. |
| The server "{server_name}" is requesting this data. |
| |
| [Cancel] [Submit] |
+-------------------------------------------------------------------------+
Modal View - URL Mode
+-------------------------------------------------------------------------+
| Server Request: External Action Required [x] |
+-------------------------------------------------------------------------+
| |
| "Please complete the OAuth authorization in your browser." |
| |
| ----------------------------------------------------------------------- |
| |
| The server is requesting you visit: |
| |
| +---------------------------------------------------------------------+ |
| | https://auth.example.com/oauth/authorize?client_id=abc&state=xyz | |
| +---------------------------------------------------------------------+ |
| [Copy URL] |
| |
| [Open in Browser] |
| |
| ----------------------------------------------------------------------- |
| |
| Status: Waiting for completion... (spinning) |
| |
| Elicitation ID: abc123-def456 |
| |
| WARNING: This will open an external URL. Verify the domain before |
| proceeding. |
| |
| [Cancel] |
+-------------------------------------------------------------------------+
Features:
-
Inline Display:
- Compact form showing essential fields
- Integrated with tool execution flow
- Clear connection between tool call and elicitation
- Same submit/cancel behavior as modal
-
Form Mode:
- Generate form from JSON Schema in request
- Schema restriction: Flat objects with primitive properties only (string, number, boolean, enum) - no nested objects or arrays
- Validate input before submission
- Required field indicators
- Security warning with server name
- Submit returns response to server
- Response
action: "accept" | "decline" | "cancel"
-
URL Mode:
- Display URL for user to visit
- Copy URL button
- Open in browser button
- Waiting indicator until
notifications/elicitation/completereceived - Elicitation ID display
- Domain verification warning
-
Cancel sends declined response
Roots Configuration
Accessed via Settings or Server Info panel:
+-------------------------------------------------------------------------+
| Roots Configuration |
+-------------------------------------------------------------------------+
| |
| Filesystem roots exposed to the connected server: |
| |
| +---------------------------------------------------------------------+ |
| | Name URI Actions | |
| +---------------------------------------------------------------------+ |
| | Project file:///home/user/myproject [Remove] | |
| +---------------------------------------------------------------------+ |
| | Documents file:///home/user/Documents [Remove] | |
| +---------------------------------------------------------------------+ |
| | Config file:///etc/myapp [Remove] | |
| +---------------------------------------------------------------------+ |
| |
| [+ Add Root] |
| |
| ----------------------------------------------------------------------- |
| |
| Add New Root: |
| |
| Name: |
| +---------------------------------------------------------------------+ |
| | Downloads | |
| +---------------------------------------------------------------------+ |
| |
| Path: |
| +---------------------------------------------------------------------+ |
| | /home/user/Downloads | |
| +---------------------------------------------------------------------+ |
| [Browse] [Add] |
| |
| WARNING: Roots give the server access to these directories. |
| Only add directories you trust the server to access. |
| |
+-------------------------------------------------------------------------+
Features:
- List configured roots with name and URI
- Add new roots:
- Name field
- Path field with browse button
- Remove roots
- Sends
notifications/roots/listChangedwhen roots are modified - Responds to
roots/listrequests from server - Security warning about filesystem access
Experimental Features Panel
Accessed via Settings or dedicated nav item:
+-------------------------------------------------------------------------+
| Experimental Features & Advanced Testing |
+-------------------------------------------------------------------------+
| |
| WARNING: These features are non-standard and may change or be removed. |
| |
| Server Experimental Capabilities: |
| +---------------------------------------------------------------------+ |
| | custom_analytics | |
| | Description: Custom analytics tracking | |
| | Methods: analytics/track, analytics/query | |
| | [Test ->] | |
| +---------------------------------------------------------------------+ |
| | streaming_v2 | |
| | Description: Enhanced streaming support | |
| | Methods: stream/start, stream/stop, stream/data | |
| | [Test ->] | |
| +---------------------------------------------------------------------+ |
| |
| Client Experimental Capabilities (advertised to server): |
| +---------------------------------------------------------------------+ |
| | [ ] custom_analytics | |
| | [ ] streaming_v2 | |
| | [ ] Add custom capability... | |
| +---------------------------------------------------------------------+ |
| |
| ----------------------------------------------------------------------- |
| |
| Advanced JSON-RPC Tester |
| Send raw JSON-RPC requests to test ANY method (standard or experimental)|
| |
| Custom Headers (optional): |
| +---------------------------------------------------------------------+ |
| | X-Debug-Mode | true [Remove] | |
| | X-Request-ID | test-123 [Remove] | |
| +---------------------------------------------------------------------+ |
| [+ Add Header] |
| |
| Request: |
| +---------------------------------------------------------------------+ |
| | { | |
| | "jsonrpc": "2.0", | |
| | "id": 1, | |
| | "method": "tools/call", | |
| | "params": { | |
| | "name": "echo", | |
| | "arguments": { "message": "test" }, | |
| | "_meta": { "progressToken": "abc123" } | |
| | } | |
| | } | |
| +---------------------------------------------------------------------+ |
| [Load from History v] [Send Request] |
| |
| Response: |
| +---------------------------------------------------------------------+ |
| | { | |
| | "jsonrpc": "2.0", | |
| | "id": 1, | |
| | "result": { | |
| | "content": [{ "type": "text", "text": "test" }] | |
| | } | |
| | } | |
| +---------------------------------------------------------------------+ |
| [Copy] |
| |
| Request History: |
| 14:32:05 - tools/call (success) 45ms |
| 14:31:22 - resources/list (success) 12ms |
| 14:30:01 - experimental/myMethod (error) 200ms |
| |
+-------------------------------------------------------------------------+
Features:
- Display server's experimental capabilities from initialization
- Toggle client experimental capabilities to advertise
- Add custom client experimental capabilities
- Advanced JSON-RPC Tester:
- Test ANY JSON-RPC method (not just experimental)
- Custom headers for per-request header injection
- JSON editor with syntax highlighting
- Full control over
_metaandprogressTokenfields - [Load from History] to replay previous requests
- Response display with copy button
- Request history with method, status, and duration
- Use Cases:
- Testing server behavior with invalid parameters
- Debugging SDK message formatting (see full request/response)
- Verifying
_meta/progressTokenhandling - Testing experimental methods before SDK support
- Comparing behavior across different servers
Sampling Providers & Testing Profiles
Testing Profiles allow quick switching between different sampling response strategies.
Architecture
Sampling Providers (built-in for V2):
+-- Manual - User types each response
+-- Mock/Template - Auto-respond with preconfigured templates
Testing Profiles (saved configurations):
+-- Profile selects a provider
+-- Profile configures that provider's settings
+-- Quick switch between profiles for different testing scenarios
Testing Profiles Settings
+-------------------------------------------------------------------------+
| Sampling Settings |
+-------------------------------------------------------------------------+
| |
| Active Profile: [Quick Mock v] [+ New Profile] |
| |
| Saved Profiles: |
| +---------------------------------------------------------------------+ |
| | (*) Quick Mock | Mock, auto-respond, simple template | |
| | ( ) Detailed Mock | Mock, model-specific templates | |
| | ( ) Manual Review | Manual, no auto-respond | |
| +---------------------------------------------------------------------+ |
| [Edit Selected] [Delete] |
| |
+-------------------------------------------------------------------------+
| Profile: Quick Mock [Editing] |
+-------------------------------------------------------------------------+
| |
| Profile Name: [Quick Mock ] |
| |
| Provider: [Mock/Template v] |
| |
| [x] Auto-respond to sampling requests |
| |
| Default Response Template: |
| +---------------------------------------------------------------------+ |
| | This is a mock LLM response for testing purposes. | |
| +---------------------------------------------------------------------+ |
| |
| Default Model: [mock-model-1.0 ] |
| Default Stop Reason: [end_turn v] |
| |
| Model-Specific Overrides: [+ Add] |
| +---------------------------------------------------------------------+ |
| | Pattern | Response Template | Actions | |
| +---------------------------------------------------------------------+ |
| | claude-* | "I'll analyze this as Claude would..." | [Edit] | |
| | gpt-* | "As an AI assistant, I can help..." | [Edit] | |
| +---------------------------------------------------------------------+ |
| |
| [Save Profile] [Cancel] |
+-------------------------------------------------------------------------+
Provider: Manual
User manually enters each sampling response:
- No auto-respond
- Response field starts empty
- User must type or paste response
- Best for careful testing of specific responses
Provider: Mock/Template
Automatically generates responses based on templates:
- Auto-respond enabled by default
- Default template used for all requests (unless overridden)
- Model-specific overrides match model hints with patterns:
claude-*matches any Claude model hintgpt-*matches any GPT model hint- First matching pattern wins
- Response pre-filled in UI (user can still edit before sending)
Profile Switching
Profiles can be switched from:
- Sampling Settings panel (global)
- Inline sampling request dropdown (per-request override)
- Modal sampling view dropdown
Extension Points (Future)
The provider interface is designed for future plugin extensions:
interface SamplingProvider {
name: string;
description: string;
configure(): ProviderConfig; // Returns config UI schema
respond(request: SamplingRequest, config: ProviderConfig): Promise<SamplingResponse>;
}
Built-in providers (V2):
- Manual
- Mock/Template
Future plugin examples:
- OpenAI Provider (forwards to OpenAI API)
- Anthropic Provider (forwards to Claude API)
- Ollama Provider (local LLM)
- Custom Provider (user-defined handler)
When plugins are installed, they appear as additional provider options in the profile configuration.
Form Generation
Forms are dynamically generated from JSON Schema for tool inputs, prompt arguments, and resource template variables.
Supported Field Types:
| JSON Schema Type | Form Control |
|---|---|
string | Text input |
string (enum) | Select dropdown |
string (enum with oneOf) | Select dropdown with titles |
array (enum items with anyOf) | Multi-select dropdown or checkboxes |
string (format: uri) | URL input with validation |
number / integer | Number input |
boolean | Checkbox or toggle |
array | Dynamic list with add/remove |
object | Nested fieldset |
Enum Handling (Single and Multi-select):
The MCP 2025-11-25 spec supports titled enums using oneOf/anyOf:
// Single-select enum (oneOf) - renders as dropdown
{
"type": "string",
"oneOf": [
{ "const": "small", "title": "Small (1-10 items)" },
{ "const": "medium", "title": "Medium (11-100 items)" },
{ "const": "large", "title": "Large (100+ items)" }
]
}
// Multi-select enum (anyOf with array) - renders as multi-select or checkboxes
{
"type": "array",
"items": {
"type": "string",
"anyOf": [
{ "const": "read", "title": "Read access" },
{ "const": "write", "title": "Write access" },
{ "const": "delete", "title": "Delete access" }
]
}
}
| Pattern | Form Control |
|---|---|
oneOf with const values | Single-select dropdown with titles |
anyOf with const values in array items | Multi-select dropdown or checkboxes |
Legacy enum array | Single-select dropdown (no titles) |
Note: For Shadcn, multi-select requires a third-party component (e.g., shadcn-multi-select). Mantine has built-in MultiSelect.
Schema Features:
required- Mark fields as required (*)default- Pre-fill with default valuedescription- Show as helper texttitle- Display label (used inoneOf/anyOffor enum titles)enum- Render as select dropdownminimum/maximum- Validation for numbersminLength/maxLength- Validation for strings
Complex Schema Handling:
$ref- Resolve references and render inline (when possible)anyOf/oneOf(non-enum) - Show JSON editor as fallback- Toggle between form view and JSON editor for complex cases
Error Handling UX
Toast Notifications
Transient errors and success messages shown as toasts:
+-----------------------------------------------------------+
| [check] Connected to everything-server [x] |
+-----------------------------------------------------------+
+-----------------------------------------------------------+
| [!] Tool execution failed: Invalid parameters [x] |
| [View Documentation ->] |
+-----------------------------------------------------------+
Inline Error Display
Persistent errors shown inline in context (e.g., server cards):
+-----------------------------------------------------------+
| [!] Connection Error |
| |
| Failed to connect: ECONNREFUSED |
| Retry attempt 3 of 5 |
| |
| [Show full error] [Troubleshooting Guide ->] |
+-----------------------------------------------------------+
Error Display Patterns:
- Truncation - Long errors truncated to ~100 chars with "Show more"
- Retry count - Display retry attempts for connection errors
- Doc links - Contextual links to troubleshooting documentation
- Expandable - Click to show full error message/stack trace
Connection States
Clear visual feedback for connection lifecycle:
| State | Visual | User Action |
|---|---|---|
| Disconnected | Gray status, toggle off | Click toggle to connect |
| Connecting | Yellow pulsing, spinner | Wait or cancel |
| Connected | Green status, toggle on | Click toggle to disconnect |
| Failed | Red status, error shown | Retry or edit config |
| OAuth Flow | Redirect indicator | Complete OAuth in browser |