M365 Declarative Agent Debugging Skill

Debug non-functional M365 Copilot declarative agents.

⚠️ Staleness Warning

M365 Copilot and Teams platform APIs are in rapid evolution. Schema versions, capabilities, and tooling change frequently.

Refresh triggers:

• New declarativeAgent schema versions
• M365 Agents Toolkit updates (formerly Teams Toolkit)
• New M365 Copilot capabilities
• Developer Portal changes

Last validated: February 2026 (Schema v1.6+, M365 Agents Toolkit with @m365agents chat participant)

Check current state: Declarative Agent Schema, M365 Agents Toolkit

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Available MCP Tools

The M365 Agents Toolkit exposes MCP tools via the @m365agents chat participant. Use these before manual debugging:

Tool	When to Use
mcp_m365agentstoo_get_schema	Validate manifest structure — get the current app manifest (v1.19), declarative agent (v1.0), or API plugin (v2.1) schema
mcp_m365agentstoo_troubleshoot	Diagnose common issues — schema validation failures, sideloading errors, conditional access blocks
mcp_m365agentstoo_get_knowledge	Look up M365 Copilot development knowledge — capabilities, limits, best practices
mcp_m365agentstoo_get_code_snippets	Find working examples — Teams AI, Teams JS, botbuilder code samples

Workflow integration: Always try mcp_m365agentstoo_troubleshoot first when a user reports an M365 agent issue. Use mcp_m365agentstoo_get_schema to verify manifest structure before manual schema checks.

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Schema Version Validation

Critical: Schema versions and their capabilities:

Version	Status	Key Additions
v1.0	Original baseline	Core capabilities
v1.2	Stable	WebSearch sites, GraphicArt, CodeInterpreter
v1.5	Extended	TeamsMessages, Email, People
v1.6	LATEST	Dataverse, Meetings, EmbeddedKnowledge, worker_agents

v1.3 and v1.4 DO NOT EXIST — unrecognized schema makes entire document invalid.

Capability Compatibility

Capability	v1.2	v1.5	v1.6
OneDriveAndSharePoint	✅	✅	✅
WebSearch	✅	✅	✅
GraphicArt	✅	✅	✅
CodeInterpreter	✅	✅	✅
GraphConnectors	✅	✅	✅
TeamsMessages	❌	✅	✅
Email	❌	✅	✅
People	❌	✅	✅
Meetings	❌	❌	✅
Dataverse	❌	❌	✅
EmbeddedKnowledge	❌	❌	✅ (not yet available)
ScenarioModels	❌	❌	✅

Lesson: v1.5/v1.6 capabilities with v1.2 schema = silent failure.

Manifest Limits (v1.6)

Property	Limit
name	100 characters
description	1,000 characters
instructions	8,000 characters
conversation_starters	6 items max (was 12 in v1.2)
actions	1-10 items
WebSearch.sites	4 items
TeamsMessages.urls	5 items
Meetings.items_by_id	5 items

Icon Requirements

color.png: 192×192px, solid background, logo in center 120×120 safe zone

outline.png: 32×32px, white only (#FFFFFF), transparent background (Alpha=0)

Common error:

Error: Outline icon is not transparent. Alpha,R,G,B: 255,X,X,X

Alpha=255 means opaque. Background pixels must be Alpha=0.

Debugging Workflow

1. MCP first: Call mcp_m365agentstoo_troubleshoot with the error message or symptom — this often resolves the issue immediately

2. Schema check: Call mcp_m365agentstoo_get_schema with the relevant schema type (app_manifest, declarative_agent_manifest, api_plugin_manifest) to verify structure

3. Validate package: teamsapp validate --package-file <zip> (must pass all checks)

4. Use @m365agents chat participant: Ask @m365agents in VS Code Copilot Chat for interactive troubleshooting — it has scaffolding, schema help, and guided debugging

5. Manual schema check (fallback):

   • ✅ .../declarative-agent/v1.2/schema.json
   • ❌ .../declarative-agent/v1.3/schema.json (doesn't exist)

6. Verify capabilities match schema version

7. Test icon transparency:

Add-Type -AssemblyName System.Drawing
$bmp = New-Object System.Drawing.Bitmap("outline.png")
$pixel = $bmp.GetPixel(0, 0)
$bmp.Dispose()
"Alpha: $($pixel.A)"  # Should be 0

Package Checklist

• manifest.json — Teams app manifest (v1.19)
• declarativeAgent.json — Agent config (v1.2)
• color.png — 192×192 solid
• outline.png — 32×32 white on transparent

Symptom → Cause

Symptom	Likely Cause	MCP Tool
Agent not responding	Invalid schema version	mcp_m365agentstoo_troubleshoot
Only 1 conversation starter	Schema validation failed	mcp_m365agentstoo_get_schema
Validation errors on icon	Wrong transparency/size	— (manual check)
Capability not working	Schema version mismatch	mcp_m365agentstoo_get_knowledge
Sideloading fails	Admin policy or manifest error	mcp_m365agentstoo_troubleshoot

Memory via OneDrive

Agent reads from OneDrive using OneDriveAndSharePoint capability:

1. User creates Alex-Memory/ folder in OneDrive
2. User shares folder link in chat
3. Agent reads cognitive files from shared folder
4. For writes: Alex generates content → user pastes

Benefits: No Azure Functions, no API costs, user controls data.

Deployment Flow

npx teamsapp package --env local
npx teamsapp validate --package-file appPackage/build/*.zip
# Upload to Developer Portal → Preview in Teams

Synapses

See synapses.json for connections.