platform-lsp-integrate

Using the Salesforce LSP

The salesforce-development plugin hosts a local MCP server named

salesforce-lsp that lazily spawns Salesforce Language Server children and

exposes their semantic capabilities as MCP tools. This skill is the contract

other skills follow when they call those tools, and the answer to "how do I use

the Salesforce LSP?" — what each tool does, how to read its result, what every

error code means, and how to fall back when the host is absent.

This is a documentation/reference skill. It does not author or deploy code; it

tells you (and other skills) how to drive the LSP tools correctly.

> This plugin build vendors Apex + SOQL only. The salesforce-lsp host

> ships the Apex language server (@salesforce/apex-ls) and the SOQL language

> server. The LWC language server is intentionally not bundled in this

> plugin — the lwc.* tools are registered by the host but will always return

> an unavailable-class envelope here. Treat any lwc.* call as unavailable

> and use the fallback (read the component source / deploy-compile).

When to Use This Skill

• A user asks how to use the Salesforce LSP, or which LSP/MCP tools are available.
• A user asks what a specific tool does (apex.diagnostics, validate_soql,

complete_soql, etc.) or how to read its output.

• An LSP tool returned an error envelope (lsp_disabled, spawn_timeout,

circuit_open, no_apex_workspace, no_org_connected) and you need to know

what it means and how to recover.

• You're authoring or reviewing another skill that calls an LSP tool and need the

canonical call/fallback pattern.

• The LSP seems broken and you need to debug it (lsp.health,

${CLAUDE_PLUGIN_ROOT}/bin/lsp-doctor, the kill switch).

The Tools

All tools are served by the MCP server salesforce-lsp (invoke names follow

the plugin-prefixed pattern:

mcp__plugin_salesforce-development_salesforce-lsp__<tool_name>, where dots in

tool names become underscores — e.g. apex.diagnostics becomes

mcp__plugin_salesforce-development_salesforce-lsp__apex_diagnostics). Spawning

is lazy: a tool that needs a language server brings the child up on first call (a

one-time cold start of a few seconds for Apex), then reuses it. The pure

static-analysis tools never spawn anything.

Apex (spawns the Apex LSP)

| Tool | Purpose | Key input | Key output |

|---|---|---|---|

| apex.diagnostics | Compile-check a .cls/.trigger; surface errors/warnings | { filePath } | { ok, diagnostics: [{ line, column, severity, message }] } |

| apex.hover | Type/signature at a position | { filePath, line, character } | hover markdown |

| apex.documentSymbol | Outline of a file's symbols | { filePath } | symbol tree |

| apex.completion | Code-completion at a position | { filePath, line, character } | completion items |

SOQL

| Tool | Purpose | Spawns? | Key output |

|---|---|---|---|

| validate_soql | Parse a SOQL string for syntax errors | SOQL LSP | { ok, diagnostics: [{ line, column, severity, message }] } |

| complete_soql | Schema-aware completion at a cursor (SObjects, fields, picklist values resolved against the org) | SOQL LSP | { ok, items, expanded, unresolved, hint? } |

| extract_soql_from_apex | Statically pull every inline [SELECT …] out of Apex | No (pure static) | { ok, totalQueries, totalDynamic, files } |

| check_soql_selectivity | Selectivity heuristics (optional org LIMIT-0 probe) | No by default | selectivity report |

| refresh_org_schema | Invalidate the cached org describe so completion re-fetches | No | { ok, removed } |

> Just deployed a field/object and it won't resolve? When a SOQL or Apex

> reference to a freshly-deployed field fails (e.g. No such column 'Foo__c',

> or complete_soql doesn't offer it) right after a deploy, the cached org

> describe is stale — call refresh_org_schema to invalidate it, then re-run

> the check before assuming a code error or renaming anything. This is the lever

> for post-deploy schema lag; reach for it before treating the failure as a bug

> in your query/class. (It only clears the local cache; it can't speed up

> server-side propagation, so if the org itself hasn't finished publishing the

> field, re-running after a moment is the fallback.)

LWC — not available in this build

The lwc.* tools (lwc.diagnostics, lwc.hover, lwc.definition,

lwc.completion, lwc.workspace_symbols) are registered by the host but the LWC

language server is not vendored in this plugin. Every lwc.* call returns an

unavailable envelope. For LWC work, fall back to reading the component

source/templates directly or deploy-compiling and reading the CLI errors.

Diagnostics / health

| Tool | Purpose | Spawns? |

|---|---|---|

| lsp.health | Read-only view of kill-switch mode, workspace, per-server state, circuit-breaker state, cold-spawn timing, apex-ls version | No — never spawns |

Coordinates everywhere are one-based (line/column). validate_soql

diagnostic coordinates are relative to the query string, not a file — when a

query came from extract_soql_from_apex, translate back using that query's range.

The Call / Fallback Contract

Every skill that calls an LSP tool follows the same three rules:

1. Prefer the LSP tool over guessing. If a tool exists for the step (validate

a query, compile-check a class, complete against the org schema), call it

before falling back to hand-analysis.

1. Treat an error envelope as "unavailable," never as "passed." A tool may

return { error: <code> } instead of a result (see Error Codes). On any such

code, record <tool>=unavailable: <code> in your report and continue down the

fallback path — never report the input as valid/clean just because the

check didn't run.

1. Degrade, don't fail. The LSP is an accelerator, not a hard dependency. If

the host isn't available at all, the salesforce-lsp tools simply won't

exist — fall back to the CLI/manual path for that step and say so.

When the LSP host is absent

If the plugin/host isn't available, the MCP tools above are not registered, so a

call to (e.g.) validate_soql will not resolve. Detect this the same way you

detect an error envelope — the tool is unavailable — and use the documented

fallback:

| LSP tool unavailable | Fallback |

|---|---|

| apex.diagnostics | Deploy/compile via sf project deploy and read CLI errors |

| validate_soql | Smoke-check by running the query read-only via sf data query --json (a parse error surfaces in the CLI error) |

| complete_soql | sf sobject describe --sobject <O> --json for fields; author from the user's stated names |

| extract_soql_from_apex | Read the file(s) and locate [SELECT … ] by hand |

| apex.completion / apex.hover | Read the source directly |

| lwc.* (always unavailable here) | Read the component source/templates directly, or deploy-compile and read CLI errors |

Error Codes

A tool returns { error: <code> } (or, for complete_soql, a hint) instead of

a result. Each maps to a recovery:

| Code | Meaning | What to do |

|---|---|---|

| lsp_disabled | The kill switch (SFDX_LSP) forbids this language | Use the non-LSP fallback; or re-enable the LSP (see Debugging) |

| spawn_timeout | The language server didn't come up in time | Retry once; if it persists, fall back and run ${CLAUDE_PLUGIN_ROOT}/bin/lsp-doctor |

| circuit_open | Repeated spawn failures tripped the breaker; calls are short-circuited | Fall back now; investigate with lsp.health / ${CLAUDE_PLUGIN_ROOT}/bin/lsp-doctor |

| no_apex_workspace | No classes/*.cls under any package dir — Apex tools won't spawn | Expected in a non-Apex project; nothing to check |

| no_org_connected | (complete_soql hint) org schema couldn't be resolved | Keyword completion still works; ask for exact field/object names or connect an org. Do not surface __…_PLACEHOLDER labels as real fields |

The first three are transient/config states shared by every spawning tool; the

rest are expected, healthy states for a particular workspace/org/file context —

not signs of a broken install. (no_lwc_bundles / unsupported_lwc_file are

LWC-only codes; in this build the LWC server is not vendored, so lwc.* returns

unavailable regardless.)

Debugging the LSP

Three layers, cheapest first:

1. lsp.health (MCP tool). The fastest check — never spawns a child. Reports

the kill-switch mode, resolved workspace, per-server status, circuit-breaker

state, last cold-spawn timing, and the vendored apex-ls version. Ask Claude to

"run lsp.health," or call the lsp.health tool directly.

1. bin/lsp-doctor (CLI). A deeper, install-level diagnostic for support and

onboarding. Verifies the committed bundles exist, the vendored apex-ls

artifacts resolve, the org-schema cache is parseable, and each LSP child can

actually spawn. Exits 0 when healthy, 1 with structured per-check output

when something is wrong.

   "${CLAUDE_PLUGIN_ROOT}"/bin/lsp-doctor            # human-readable report
   "${CLAUDE_PLUGIN_ROOT}"/bin/lsp-doctor --json     # machine-readable
   "${CLAUDE_PLUGIN_ROOT}"/bin/lsp-doctor --no-spawn # skip child-spawn probes (CI/restricted)

(In this build lsp-doctor will report the LWC server as missing — that is

expected; only Apex + SOQL are vendored here.)

1. SFDX_LSP_DEBUG=1. Emits single-line JSON telemetry (spawn timing, cache

hits, circuit events, per-tool latency) to stderr. Off by default (zero

overhead).

The kill switch — SFDX_LSP

The fast way to control or disable the LSP. Set the environment variable:

| SFDX_LSP | Effect |

|---|---|

| unset / all | Every vendored LSP may spawn (default) |

| apex-only | Only the Apex LSP may spawn; SOQL tools return lsp_disabled |

| disabled | No LSP spawns; every LSP tool returns lsp_disabled |

To rule the LSP in or out of a problem, set SFDX_LSP=disabled and re-run: if the

issue persists it isn't the LSP, and skills will have fallen back to their non-LSP

paths automatically. An unknown value defaults to all (with a warning) so a typo

never silently disables the feature.

Pre-deploy diagnostics gate

A PreToolUse hook (bin/lsp-precheck) runs Apex diagnostics on the

.cls/.trigger files a sf project deploy start/validate is about to push,

and emits a decision. It is fail-open: any error (including a missing/slow

LSP) allows the deploy. Mode is controlled by SFDX_LSP_DEPLOY_GATE

(off | warn | block, default warn) — warn surfaces diagnostics without

blocking; block denies a deploy that has Apex compile errors.

Verification

• Asked "how do I use the Salesforce LSP tools?", this skill is the match and lists

the tools, their inputs/outputs, and the fallback contract.

• Appears in the /skills listing as platform-lsp-integrate.
• Given an error code (e.g. no_apex_workspace), it explains the meaning and the

correct recovery without treating the unrun check as a pass.

Cross-Skill Integration

| Need | Delegate to |

|---|---|

| Compile-check + analyze Apex you just wrote | platform-apex-generate |

| Validate inline SOQL in .cls/.trigger | validate_soql (this skill); fallback: run read-only via sf data query --json |

| Author & run a SOQL query against the org | complete_soql + sf data query |

| Pre-deploy diagnostics gate behavior | see "Pre-deploy diagnostics gate" above |