feat: Implement MCP server instruction fetching and integration

.dictate.toml

@@ -0,0 +1,99 @@
+# Dictator Configuration
+# Decree-based structural enforcement for code quality
+# Generated by: dictator occupy
+
+[decree.supreme]
+# Universal structural rules (applies to ALL files unless overridden)
+trailing_whitespace = "deny"
+tabs_vs_spaces = "spaces"
+tab_width = 2
+final_newline = "require"
+line_endings = "lf"
+blank_line_whitespace = "deny"
+# max_line_length: opt-in per language (uncomment to enforce globally)
+
+# Per-rule ignores (decree-level, not language-level)
+# - Makefiles require tabs for recipes
+# - Markdown can contain tabs inside code blocks
+[decree.supreme.ignore.tab-character]
+filenames = ["Makefile", "GNUmakefile", "makefile"]
+extensions = ["md", "mdx"]
+
+# Language-specific decrees (uncomment to enable)
+# Remove the '#' from '[decree.LANGUAGE]' and its settings to activate
+
+# [decree.ruby]
+# # Ruby-specific structural enforcement
+# max_line_length = 120
+# max_lines = 300
+# ignore_comments = true
+# ignore_blank_lines = true
+# method_visibility_order = ["public", "protected", "private"]
+# comment_spacing = true
+#
+# # External linter integration (uncomment to enable)
+# [decree.ruby.linter]
+# command = "rubocop"
+
+# [decree.typescript]
+# # TypeScript/JavaScript structural enforcement
+# max_line_length = 100
+# max_lines = 350
+# ignore_comments = true
+# ignore_blank_lines = true
+# import_order = ["system", "external", "internal"]
+#
+# # External linter integration (uncomment to enable)
+# [decree.typescript.linter]
+# command = "eslint"
+
+# [decree.golang]
+# # Go structural enforcement
+# # Go convention: tabs, not spaces (overrides decree.supreme)
+# tabs_vs_spaces = "tabs"
+# max_line_length = 120
+# max_lines = 450
+# ignore_comments = true
+# ignore_blank_lines = true
+#
+# # External linter integration (uncomment to enable)
+# [decree.golang.linter]
+# command = "gofmt"
+
+# [decree.rust]
+# # Rust structural enforcement
+# tab_width = 4
+# max_line_length = 100
+# max_lines = 400
+# ignore_comments = true
+# ignore_blank_lines = true
+# visibility_order = ["pub", "private"]
+#
+# # External linter integration (uncomment to enable)
+# [decree.rust.linter]
+# command = "clippy"
+
+# [decree.python]
+# # Python structural enforcement
+# tab_width = 4
+# max_line_length = 88
+# max_lines = 380
+# ignore_comments = true
+# ignore_blank_lines = true
+# import_order = ["stdlib", "third_party", "local"]
+#
+# # External linter integration (uncomment to enable)
+# [decree.python.linter]
+# command = "ruff"
+
+# [decree.frontmatter]
+# # YAML frontmatter ordering for .md and .mdx files only
+# # Does NOT handle: .astro (JS/TS frontmatter), .yml/.yaml, .toml
+# order = ["title", "slug", "pubDate", "description", "tags", "draft"]
+# required = ["title", "slug"]
+
+# Custom decrees (WASM/native plugins)
+# Uncomment and configure to enable custom linting rules
+# [decree.kjr]
+# enabled = true
+# path = "path/to/dictator_kjr.wasm"

packages/opencode/.dictate.toml

@@ -0,0 +1,97 @@
+# Dictator Configuration
+# Decree-based structural enforcement for code quality
+# Generated by: dictator occupy
+
+[decree.supreme]
+# Universal structural rules (applies to ALL files unless overridden)
+trailing_whitespace = "deny"
+tabs_vs_spaces = "spaces"
+tab_width = 2
+final_newline = "require"
+line_endings = "lf"
+blank_line_whitespace = "deny"
+# max_line_length: opt-in per language (uncomment to enforce globally)
+
+# Per-rule ignores (decree-level, not language-level)
+# - Makefiles require tabs for recipes
+# - Markdown can contain tabs inside code blocks
+[decree.supreme.ignore.tab-character]
+filenames = ["Makefile", "GNUmakefile", "makefile"]
+extensions = ["md", "mdx"]
+
+# Language-specific decrees (uncomment to enable)
+# Remove the '#' from '[decree.LANGUAGE]' and its settings to activate
+
+# [decree.ruby]
+# # Ruby-specific structural enforcement
+# max_line_length = 120
+# max_lines = 300
+# ignore_comments = true
+# ignore_blank_lines = true
+# method_visibility_order = ["public", "protected", "private"]
+# comment_spacing = true
+#
+# # External linter integration (uncomment to enable)
+# [decree.ruby.linter]
+# command = "rubocop"
+
+# [decree.typescript]
+# # TypeScript/JavaScript structural enforcement
+# max_line_length = 100
+# max_lines = 350
+# ignore_comments = true
+# ignore_blank_lines = true
+# import_order = ["system", "external", "internal"]
+#
+# # External linter integration (uncomment to enable)
+# [decree.typescript.linter]
+# command = "eslint"
+
+# [decree.golang]
+# # Go structural enforcement
+# # Go convention: tabs, not spaces (overrides decree.supreme)
+# tabs_vs_spaces = "tabs"
+# max_line_length = 120
+# max_lines = 450
+# ignore_comments = true
+# ignore_blank_lines = true
+#
+# # External linter integration (uncomment to enable)
+# [decree.golang.linter]
+# command = "gofmt"
+
+# [decree.rust]
+# # Rust structural enforcement
+# max_line_length = 100
+# max_lines = 400
+# ignore_comments = true
+# ignore_blank_lines = true
+# visibility_order = ["pub", "private"]
+#
+# # External linter integration (uncomment to enable)
+# [decree.rust.linter]
+# command = "clippy"
+
+# [decree.python]
+# # Python structural enforcement
+# max_line_length = 88  # Black's default
+# max_lines = 380
+# ignore_comments = true
+# ignore_blank_lines = true
+# import_order = ["stdlib", "third_party", "local"]
+#
+# # External linter integration (uncomment to enable)
+# [decree.python.linter]
+# command = "ruff"
+
+# [decree.frontmatter]
+# # YAML frontmatter ordering for .md and .mdx files only
+# # Does NOT handle: .astro (JS/TS frontmatter), .yml/.yaml, .toml
+# order = ["title", "slug", "pubDate", "description", "tags", "draft"]
+# required = ["title", "slug"]
+
+# Custom decrees (WASM/native plugins)
+# Uncomment and configure to enable custom linting rules
+# [decree.kjr]
+# enabled = true
+# path = "path/to/dictator_kjr.wasm"

packages/opencode/src/mcp/index.ts

@@ -46,6 +46,13 @@ export namespace MCP {
     }),
   )
 
+  export const InstructionsChanged = BusEvent.define(
+    "mcp.instructions.changed",
+    z.object({
+      server: z.string(),
+    }),
+  )
+
   export const BrowserOpenFailed = BusEvent.define(
     "mcp.browser.open.failed",
     z.object({
@@ -166,7 +173,9 @@ export namespace MCP {
       const config = cfg.mcp ?? {}
       const clients: Record<string, MCPClient> = {}
       const status: Record<string, Status> = {}
+      const serverInstructions: Record<string, string> = {}
 
+      // Discover all configured MCP servers
       await Promise.all(
         Object.entries(config).map(async ([key, mcp]) => {
           if (!isMcpConfigured(mcp)) {
@@ -187,12 +196,20 @@ export namespace MCP {
 
           if (result.mcpClient) {
             clients[key] = result.mcpClient
+            // Fetch and cache instructions during initialization
+            const instructions = await fetchServerInstructions(key, result.mcpClient)
+            if (instructions) {
+              serverInstructions[key] = instructions
+              log.info("cached server instructions", { key })
+            }
           }
         }),
       )
+
       return {
         status,
         clients,
+        serverInstructions,
       }
     },
     async (state) => {
@@ -209,6 +226,23 @@ export namespace MCP {
     },
   )
 
+  // Helper function to fetch server instructions from an MCP client
+  // Server instructions are always fetched automatically per MCP protocol specification
+  async function fetchServerInstructions(serverName: string, client: MCPClient): Promise<string | undefined> {
+    try {
+      const instructions = await client.getInstructions()
+      if (instructions?.trim()) {
+        return instructions
+      }
+
+      log.debug("no server instructions available", { serverName })
+      return undefined
+    } catch (error) {
+      log.debug("failed to fetch server instructions", { serverName, error })
+      return undefined
+    }
+  }
+
   // Helper function to fetch prompts for a specific client
   async function fetchPromptsForClient(clientName: string, client: Client) {
     const prompts = await client.listPrompts().catch((e) => {
@@ -254,6 +288,56 @@ export namespace MCP {
     return commands
   }
 
+  /**
+   * Refresh server instructions for a specific MCP server.
+   */
+  export async function refreshServerInstructions(serverName: string) {
+    const s = await state()
+    const client = s.clients[serverName]
+
+    if (!client) {
+      log.warn("cannot refresh instructions: client not found", { serverName })
+      return
+    }
+
+    const instructions = await fetchServerInstructions(serverName, client)
+    if (instructions) {
+      // Update the server instructions in state
+      s.serverInstructions = s.serverInstructions || {}
+      s.serverInstructions[serverName] = instructions
+      log.info("refreshed server instructions", { serverName })
+      // Publish event for instruction changes
+      Bus.publish(InstructionsChanged, { server: serverName })
+    }
+  }
+
+  /**
+   * Refresh server instructions for all connected MCP servers.
+   */
+  export async function refreshAllServerInstructions() {
+    const s = await state()
+
+    const refreshPromises = Object.keys(s.clients).map(async (serverName) => {
+      try {
+        const client = s.clients[serverName]
+        if (!client) return
+
+        const instructions = await fetchServerInstructions(serverName, client)
+        if (instructions) {
+          s.serverInstructions = s.serverInstructions || {}
+          s.serverInstructions[serverName] = instructions
+          log.info("refreshed server instructions", { serverName })
+          // Publish event for instruction changes
+          Bus.publish(InstructionsChanged, { server: serverName })
+        }
+      } catch (error) {
+        log.error("failed to refresh server instructions", { serverName, error })
+      }
+    })
+
+    await Promise.all(refreshPromises)
+  }
+
   export async function add(name: string, mcp: Config.Mcp) {
     const s = await state()
     const result = await create(name, mcp)
@@ -513,6 +597,10 @@ export namespace MCP {
     return state().then((state) => state.clients)
   }
 
+  export async function serverInstructions() {
+    return state().then((state) => state.serverInstructions || {})
+  }
+
   export async function connect(name: string) {
     const cfg = await Config.get()
     const config = cfg.mcp ?? {}

packages/opencode/src/session/llm.ts

@@ -66,19 +66,30 @@ export namespace LLM {
     const isCodex = provider.id === "openai" && auth?.type === "oauth"
 
     const system = SystemPrompt.header(input.model.providerID)
-    system.push(
-      [
-        // use agent prompt otherwise provider prompt
-        // For Codex sessions, skip SystemPrompt.provider() since it's sent via options.instructions
-        ...(input.agent.prompt ? [input.agent.prompt] : isCodex ? [] : SystemPrompt.provider(input.model)),
-        // any custom prompt passed into this call
-        ...input.system,
-        // any custom prompt from last user message
-        ...(input.user.system ? [input.user.system] : []),
-      ]
-        .filter((x) => x)
-        .join("\n"),
-    )
+
+    // Get MCP server instructions - handle errors gracefully
+    let mcpInstructions: string[] = []
+    try {
+      mcpInstructions = await SystemPrompt.mcpInstructions()
+    } catch (error) {
+      // Silently ignore MCP instruction errors to avoid breaking the system
+    }
+
+    const systemText = [
+      // use agent prompt otherwise provider prompt
+      // For Codex sessions, skip SystemPrompt.provider() since it's sent via options.instructions
+      ...(input.agent.prompt ? [input.agent.prompt] : isCodex ? [] : SystemPrompt.provider(input.model)),
+      // any custom prompt passed into this call
+      ...input.system,
+      // any custom prompt from last user message
+      ...(input.user.system ? [input.user.system] : []),
+      // Include MCP server instructions
+      ...mcpInstructions,
+    ]
+      .filter((x) => x)
+      .join("\n")
+
+    system.push(systemText)
 
     const header = system[0]
     const original = clone(system)