Feature Request: MCP Profiles for Rapid Context-Aware Tool Switching

Problem

MCP configuration is currently all-or-nothing: configure an MCP server and it becomes available everywhere (Claude Code, Cowork, all projects). This creates three operational pain points:

1. Context waste from unintended MCPs: Developers configure MCPs for Cowork workflows (e.g., Slack for knowledge work) and those tools now consume 10-15% of Claude Code's context budget—even when Code doesn't need them. There's no way to disable them without removing them entirely.

1. No scoped tool management: disallowedTools flag doesn't work for MCP servers (#12863). Project-level exclusion doesn't work (#8321). Developers must manually edit .claude.json between sessions or maintain separate machine profiles—friction that breaks rapid task switching.

1. Behavioral drift: Without tool scoping, Claude Code may autonomously search/use MCPs it wasn't intended to access. Example: mentioning a person's name while working on a GitHub issue triggers Slack searches—unexpected autonomous behavior that requires explicit negative instructions to prevent.

Solution: MCP Profiles

Implement bundled MCP profiles that can be loaded, switched, and hotloaded per context:

\\\json
{
"mcp": {
"profiles": {
"coding": {
"description": "Claude Code defaults",
"mcpServers": {
"github": { "..." : "..." },
"context7": { "..." : "..." }
}
},
"knowledge-work": {
"description": "Cowork defaults",
"mcpServers": {
"slack": { "..." : "..." },
"notion": { "..." : "..." },
"github": { "..." : "..." }
}
},
"web-automation": {
"mcpServers": {
"playwright": { "..." : "..." },
"web-fetch": { "..." : "..." }
}
},
"empty": {
"description": "No MCPs",
"mcpServers": {}
}
},
"defaults": {
"code": "coding",
"cowork": "knowledge-work",
"project": "coding"
}
}
}
\\\

Scoping Options

• Tool-level: \cowork\ profiles only, \code\ profiles only, \shared\
• Session-level: Load profile at startup via flag: \claude --mcp-profile coding\
• Project-level: \.mcp.json\ or \.claude/settings.json\ specifies profile override
• Runtime hotloading: \/mcp-profile switch knowledge-work\ to reload MCPs mid-session
• Default fallback: Allow \null\ or empty profile to load nothing

Benefits

1. Context preservation: Developers keep only needed MCPs in context per tool/session
2. Rapid switching: Bundle management, not individual MCP toggling. Switching profiles takes one command
3. Predictable behavior: Claude Code only has access to MCPs explicitly in its profile; no autonomous searches outside scope
4. Team alignment: Profiles can be committed to \.claude/profiles/\ and shared across team
5. Backward compatible: Default behavior preloads all MCPs if no profile specified

Implementation Notes

• Profiles should be loadable from:
• User level: \~/.claude/mcp-profiles.json\
• Project level: \.claude/mcp-profiles.json\
• System level: \/etc/claude/mcp-profiles.json\
• Profile inheritance: Project profiles override user profiles; explicit flags override both
• Hotloading should trigger context recalculation (show \/context\ output after switch)

Real-world Use Case

Platform engineer working on infrastructure:

• "coding" profile: GitHub, context7, Netbox (IaC tooling for Terraform/Kubernetes work)
• "knowledge-work" profile: Slack, Notion, Linear (knowledge synthesis, incident response)
• "empty" profile: When pair debugging with sensitive credentials in terminal

Today: Loses 10% context to Slack MCPs in Code sessions. Must manually edit config to exclude them. Behavior is unpredictable.

With profiles: \claude --mcp-profile coding\ in morning, \claude --mcp-profile knowledge-work\ for incident review. MCPs load/unload atomically. Behavior is explicit.

Note on Existing Issues

This feature request subsumes:

• #7328: MCP tool filtering (granular)
• #7289: Disabling MCP in specific contexts
• #8321: Project-level MCP exclusion

Profiles solve the bundle-scoping problem with less API surface area and more user control.