[Feature]: Env-var opt-out for the main-session WebFetch deny (e.g. CONTEXT_MODE_ALLOW_WEBFETCH=1)

[rrva]

Summary

The PreToolUse WebFetch branch hard-denies WebFetch in the main session and redirects to ctx_fetch_and_index (hooks/core/routing.mjs ~L800, action: "deny"). This is intentional and valuable as a default, but there is currently no first-class way to opt out of just this interception while keeping the rest of context-mode enabled. I'd like to request an env-var opt-out, e.g. CONTEXT_MODE_ALLOW_WEBFETCH=1, checked in the canonical === "WebFetch" branch and returning pass-through (null) when set.

Environment

• context-mode 1.0.162 (plugin via marketplace), Claude Code CLI, macOS
• MCP server running normally in the main session (ctx_doctor all green)

Why this is needed

Confirmed (source + DeepWiki) that no env var, config file, or per-tool allowlist/denylist disables the WebFetch deny — the routing is hardcoded. The only way to restore WebFetch today is to edit the plugin-cache hooks/hooks.json (drop the WebFetch matcher) or patch the routing.mjs branch to return null. Both work, but live under the install-cache path and are silently overwritten on every plugin update, so they aren't durable.

There are legitimate reasons to want WebFetch directly in the main session:

• WebFetch's built-in prompt-based extraction (fetch + summarize in one model pass) is a different workflow from ctx_fetch_and_index + ctx_search; for small/one-off pages the index round-trip is more overhead than the bytes saved (overlaps with PreToolUse/PostToolUse hooks intercept small Bash/WebFetch calls without a size threshold (Claude Code) — unlike Gemini CLI's size-aware BeforeTool matcher #817).
• Users who have their own context discipline and just want the native tool back, without losing the Bash/Read/Grep nudges, the ctx_* sandbox tools, or session capture.

Precedent

This is the same shape already requested for a different hook branch in #832 (CONTEXT_MODE_DISABLE_AGENT_INJECTION=1 for the Agent-injection branch). A symmetric WebFetch flag would be consistent with that, and with the existing env-var surface (CONTEXT_MODE_REQUIRE_SECURITY, CONTEXT_MODE_PLATFORM, CONTEXT_MODE_DEBUG, …).

Relationship to existing issues

• PreToolUse/PostToolUse hooks intercept small Bash/WebFetch calls without a size threshold (Claude Code) — unlike Gemini CLI's size-aware BeforeTool matcher #817 (open) — proposes a size threshold for Bash/WebFetch interception. Related, but a binary opt-out is a simpler, orthogonal escape hatch (and useful even if a threshold lands).
• PreToolUse WebFetch deny hard-blocks subagents that cannot access ctx_* MCP tools (isMCPReady is machine-global, tool availability is per-agent-context) #794 (open) — subagent-context WebFetch passthrough; different scope (per-agent-context), this request is about the main session.
• [Feature]: Env-var opt-out for subagent Agent-injection - foreground agents can hang on forced ctx_* calls #832 (open) — env-var opt-out for Agent-injection; same pattern, sibling branch.
• PreToolUse hooks are too invasive — blocks WebFetch, replaces curl/wget, injects prompts into Read, with no opt-out #79 (closed) — "PreToolUse hooks are too invasive — blocks WebFetch".

Proposed (any one resolves it)

1. Env-var opt-out CONTEXT_MODE_ALLOW_WEBFETCH=1 (or CONTEXT_MODE_DISABLE_WEBFETCH_REDIRECT=1), checked in the canonical === "WebFetch" branch of routing.mjs, returning null (pass-through) instead of the deny.
2. A more general per-tool deny/allow list config covering WebFetch (would also subsume parts of PreToolUse/PostToolUse hooks intercept small Bash/WebFetch calls without a size threshold (Claude Code) — unlike Gemini CLI's size-aware BeforeTool matcher #817/[Feature]: Env-var opt-out for subagent Agent-injection - foreground agents can hang on forced ctx_* calls #832).
3. At minimum, document that the WebFetch deny exists and how to disable it.

Rationale for opt-out over removal: the default deny stays for everyone who wants it; this only adds an escape hatch.

Happy to send a PR for option 1 if you're open to it.

🤖 Filed with Claude Code