mcp_server.rs

  1use std::path::PathBuf;
  2
  3use acp_thread::AcpThread;
  4use agent_client_protocol as acp;
  5use anyhow::{Context, Result};
  6use collections::HashMap;
  7use context_server::types::{
  8    CallToolParams, CallToolResponse, Implementation, InitializeParams, InitializeResponse,
  9    ListToolsResponse, ProtocolVersion, ServerCapabilities, Tool, ToolAnnotations,
 10    ToolResponseContent, ToolsCapabilities, requests,
 11};
 12use gpui::{App, AsyncApp, Entity, Task, WeakEntity};
 13use schemars::JsonSchema;
 14use serde::{Deserialize, Serialize};
 15
 16use crate::claude::tools::{ClaudeTool, EditToolParams, ReadToolParams};
 17
 18pub struct ClaudeZedMcpServer {
 19    server: context_server::listener::McpServer,
 20}
 21
 22pub const SERVER_NAME: &str = "zed";
 23pub const READ_TOOL: &str = "Read";
 24pub const EDIT_TOOL: &str = "Edit";
 25pub const PERMISSION_TOOL: &str = "Confirmation";
 26
 27#[derive(Deserialize, JsonSchema, Debug)]
 28struct PermissionToolParams {
 29    tool_name: String,
 30    input: serde_json::Value,
 31    tool_use_id: Option<String>,
 32}
 33
 34#[derive(Serialize)]
 35#[serde(rename_all = "camelCase")]
 36struct PermissionToolResponse {
 37    behavior: PermissionToolBehavior,
 38    updated_input: serde_json::Value,
 39}
 40
 41#[derive(Serialize)]
 42#[serde(rename_all = "snake_case")]
 43enum PermissionToolBehavior {
 44    Allow,
 45    Deny,
 46}
 47
 48impl ClaudeZedMcpServer {
 49    pub async fn new(
 50        thread_rx: watch::Receiver<WeakEntity<AcpThread>>,
 51        cx: &AsyncApp,
 52    ) -> Result<Self> {
 53        let mut mcp_server = context_server::listener::McpServer::new(cx).await?;
 54        mcp_server.handle_request::<requests::Initialize>(Self::handle_initialize);
 55        mcp_server.handle_request::<requests::ListTools>(Self::handle_list_tools);
 56        mcp_server.handle_request::<requests::CallTool>(move |request, cx| {
 57            Self::handle_call_tool(request, thread_rx.clone(), cx)
 58        });
 59
 60        Ok(Self { server: mcp_server })
 61    }
 62
 63    pub fn server_config(&self) -> Result<McpServerConfig> {
 64        let zed_path = std::env::current_exe()
 65            .context("finding current executable path for use in mcp_server")?;
 66
 67        Ok(McpServerConfig {
 68            command: zed_path,
 69            args: vec![
 70                "--nc".into(),
 71                self.server.socket_path().display().to_string(),
 72            ],
 73            env: None,
 74        })
 75    }
 76
 77    fn handle_initialize(_: InitializeParams, cx: &App) -> Task<Result<InitializeResponse>> {
 78        cx.foreground_executor().spawn(async move {
 79            Ok(InitializeResponse {
 80                protocol_version: ProtocolVersion("2025-06-18".into()),
 81                capabilities: ServerCapabilities {
 82                    experimental: None,
 83                    logging: None,
 84                    completions: None,
 85                    prompts: None,
 86                    resources: None,
 87                    tools: Some(ToolsCapabilities {
 88                        list_changed: Some(false),
 89                    }),
 90                },
 91                server_info: Implementation {
 92                    name: SERVER_NAME.into(),
 93                    version: "0.1.0".into(),
 94                },
 95                meta: None,
 96            })
 97        })
 98    }
 99
100    fn handle_list_tools(_: (), cx: &App) -> Task<Result<ListToolsResponse>> {
101        cx.foreground_executor().spawn(async move {
102            Ok(ListToolsResponse {
103                tools: vec![
104                    Tool {
105                        name: PERMISSION_TOOL.into(),
106                        input_schema: schemars::schema_for!(PermissionToolParams).into(),
107                        description: None,
108                        annotations: None,
109                    },
110                    Tool {
111                        name: READ_TOOL.into(),
112                        input_schema: schemars::schema_for!(ReadToolParams).into(),
113                        description: Some("Read the contents of a file. In sessions with mcp__zed__Read always use it instead of Read as it contains the most up-to-date contents.".to_string()),
114                        annotations: Some(ToolAnnotations {
115                            title: Some("Read file".to_string()),
116                            read_only_hint: Some(true),
117                            destructive_hint: Some(false),
118                            open_world_hint: Some(false),
119                            // if time passes the contents might change, but it's not going to do anything different
120                            // true or false seem too strong, let's try a none.
121                            idempotent_hint: None,
122                        }),
123                    },
124                    Tool {
125                        name: EDIT_TOOL.into(),
126                        input_schema: schemars::schema_for!(EditToolParams).into(),
127                        description: Some("Edits a file. In sessions with mcp__zed__Edit always use it instead of Edit as it will show the diff to the user better.".to_string()),
128                        annotations: Some(ToolAnnotations {
129                            title: Some("Edit file".to_string()),
130                            read_only_hint: Some(false),
131                            destructive_hint: Some(false),
132                            open_world_hint: Some(false),
133                            idempotent_hint: Some(false),
134                        }),
135                    },
136                ],
137                next_cursor: None,
138                meta: None,
139            })
140        })
141    }
142
143    fn handle_call_tool(
144        request: CallToolParams,
145        mut thread_rx: watch::Receiver<WeakEntity<AcpThread>>,
146        cx: &App,
147    ) -> Task<Result<CallToolResponse>> {
148        cx.spawn(async move |cx| {
149            let Some(thread) = thread_rx.recv().await?.upgrade() else {
150                anyhow::bail!("Thread closed");
151            };
152
153            if request.name.as_str() == PERMISSION_TOOL {
154                let input =
155                    serde_json::from_value(request.arguments.context("Arguments required")?)?;
156
157                let result = Self::handle_permissions_tool_call(input, thread, cx).await?;
158                Ok(CallToolResponse {
159                    content: vec![ToolResponseContent::Text {
160                        text: serde_json::to_string(&result)?,
161                    }],
162                    is_error: None,
163                    meta: None,
164                })
165            } else if request.name.as_str() == READ_TOOL {
166                let input =
167                    serde_json::from_value(request.arguments.context("Arguments required")?)?;
168
169                let content = Self::handle_read_tool_call(input, thread, cx).await?;
170                Ok(CallToolResponse {
171                    content,
172                    is_error: None,
173                    meta: None,
174                })
175            } else if request.name.as_str() == EDIT_TOOL {
176                let input =
177                    serde_json::from_value(request.arguments.context("Arguments required")?)?;
178
179                Self::handle_edit_tool_call(input, thread, cx).await?;
180                Ok(CallToolResponse {
181                    content: vec![],
182                    is_error: None,
183                    meta: None,
184                })
185            } else {
186                anyhow::bail!("Unsupported tool");
187            }
188        })
189    }
190
191    fn handle_read_tool_call(
192        ReadToolParams {
193            abs_path,
194            offset,
195            limit,
196        }: ReadToolParams,
197        thread: Entity<AcpThread>,
198        cx: &AsyncApp,
199    ) -> Task<Result<Vec<ToolResponseContent>>> {
200        cx.spawn(async move |cx| {
201            let content = thread
202                .update(cx, |thread, cx| {
203                    thread.read_text_file(abs_path, offset, limit, false, cx)
204                })?
205                .await?;
206
207            Ok(vec![ToolResponseContent::Text { text: content }])
208        })
209    }
210
211    fn handle_edit_tool_call(
212        params: EditToolParams,
213        thread: Entity<AcpThread>,
214        cx: &AsyncApp,
215    ) -> Task<Result<()>> {
216        cx.spawn(async move |cx| {
217            let content = thread
218                .update(cx, |threads, cx| {
219                    threads.read_text_file(params.abs_path.clone(), None, None, true, cx)
220                })?
221                .await?;
222
223            let new_content = content.replace(&params.old_text, &params.new_text);
224            if new_content == content {
225                return Err(anyhow::anyhow!("The old_text was not found in the content"));
226            }
227
228            thread
229                .update(cx, |threads, cx| {
230                    threads.write_text_file(params.abs_path, new_content, cx)
231                })?
232                .await?;
233
234            Ok(())
235        })
236    }
237
238    fn handle_permissions_tool_call(
239        params: PermissionToolParams,
240        thread: Entity<AcpThread>,
241        cx: &AsyncApp,
242    ) -> Task<Result<PermissionToolResponse>> {
243        cx.spawn(async move |cx| {
244            let claude_tool = ClaudeTool::infer(&params.tool_name, params.input.clone());
245
246            let tool_call_id =
247                acp::ToolCallId(params.tool_use_id.context("Tool ID required")?.into());
248
249            let allow_option_id = acp::PermissionOptionId("allow".into());
250            let reject_option_id = acp::PermissionOptionId("reject".into());
251
252            let chosen_option = thread
253                .update(cx, |thread, cx| {
254                    thread.request_tool_call_permission(
255                        claude_tool.as_acp(tool_call_id),
256                        vec![
257                            acp::PermissionOption {
258                                id: allow_option_id.clone(),
259                                label: "Allow".into(),
260                                kind: acp::PermissionOptionKind::AllowOnce,
261                            },
262                            acp::PermissionOption {
263                                id: reject_option_id,
264                                label: "Reject".into(),
265                                kind: acp::PermissionOptionKind::RejectOnce,
266                            },
267                        ],
268                        cx,
269                    )
270                })?
271                .await?;
272
273            if chosen_option == allow_option_id {
274                Ok(PermissionToolResponse {
275                    behavior: PermissionToolBehavior::Allow,
276                    updated_input: params.input,
277                })
278            } else {
279                Ok(PermissionToolResponse {
280                    behavior: PermissionToolBehavior::Deny,
281                    updated_input: params.input,
282                })
283            }
284        })
285    }
286}
287
288#[derive(Serialize)]
289#[serde(rename_all = "camelCase")]
290pub struct McpConfig {
291    pub mcp_servers: HashMap<String, McpServerConfig>,
292}
293
294#[derive(Serialize, Clone)]
295#[serde(rename_all = "camelCase")]
296pub struct McpServerConfig {
297    pub command: PathBuf,
298    pub args: Vec<String>,
299    #[serde(skip_serializing_if = "Option::is_none")]
300    pub env: Option<HashMap<String, String>>,
301}