[Bug] LSP freezes and diagnostics timeout too short (3s) for heavy language servers

[ojh102]

Description

Multiple users experiencing LSP-related freezes and timeouts across different scenarios:

• Kotlin LSP exceeding 45s timeout ([FEATURE]: Allow configurable timeouts to be set on LSPs #7477)
• ESLint diagnostics timing out at 3s, returning empty results (ESLint LSP server initializes but diagnostics timeout with empty result #13272)
• Windows app freezes related to blocking LSP operations (1.1.57.0 OpenCode Desktop bug after update: Freezes, terminal loop - No longer usable #13154)

Root Cause Analysis:

1. Blocking initialization: getClients() was synchronous → blocked UI thread when LSP servers were slow to start
2. Insufficient timeout defaults: Diagnostics timeout was hardcoded at 3s → too short for heavy linters like ESLint and Kotlin LSP
3. No user escape hatch: No way for users to configure timeouts for their specific environment

Related PRs:

PR	Approach	Status	Overlap with #13306
#13306	Non-blocking init + configurable diagnostics timeout	Open	Primary comprehensive fix
#13281	Diagnostics timeout 3s→10s	Open	Absorbed into #13306
#6997	Configurable timeout	Open	Partially addressed by #13306 env var
#13287	Startup package-manager timeout guard	Open	Independent (different timeout)
#13299	UI freeze on large diffs	Open	Independent (rendering issue)

Resolution Path:

Addressed by PR #13306:

• ✅ Non-blocking LSP initialization (getClients returns immediately)
• ✅ Configurable diagnostics timeout (10s default, override via OPENCODE_EXPERIMENTAL_LSP_DIAGNOSTICS_TIMEOUT_MS)

Remaining work (separate concerns):

• Startup timeout (fix(installation): guard startup package-manager probes with timeout #13287)
• UI rendering performance (perf(app): collapse large diffs in review panel to prevent UI freeze #13299)

Plugins

No response

OpenCode version

dev (latest)

Steps to reproduce

1. Open a project with a heavy LSP (e.g., Kotlin, ESLint with many plugins)
2. Start OpenCode
3. Observe: UI blocks during LSP initialization, and diagnostics timeout at 3s returning empty results for slow language servers

Screenshot and/or share link

No response

Operating System

Cross-platform (reported on macOS, Windows, Linux)

Terminal

Multiple terminals affected (not terminal-specific)

[github-actions]

This issue doesn't fully meet our contributing guidelines.

What needs to be fixed:

• This issue must use one of the three required templates: Bug Report, Feature Request, or Question. Currently it uses a custom format.
• Please reopen this as a standard Bug Report (describing the LSP freezing/timeout issues) or use the appropriate template for your issue type.

Please edit or reopen this issue to address the above within 2 hours, or it will be automatically closed.

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[ojh102]

Closing to recreate with proper Bug Report template.