feat(chat): context management and context editing

.codecompanion/chat.md

@@ -15,6 +15,7 @@ Messages in the chat buffer are lua table objects as seen. They contain the role
     _meta = {
       cycle = 1,
       id = 708950413,
+      estimated_tokens = 20,
       tag = "system_prompt_from_config",
     },
     opts = {
@@ -25,15 +26,37 @@ Messages in the chat buffer are lua table objects as seen. They contain the role
   }, {
     _meta = {
       cycle = 1,
+      estimated_tokens = 20,
       id = 533315931,
       sent = true
     },
     opts = {
       visible = true
     },
     role = "user"
-    content = "Are you working?",
-  }, {
+    content = "Are you working? Sharing a file with you",
+  },
+ {
+    _meta = {
+      cycle = 1,
+      estimated_tokens = 3556,
+      id = 1048633318,
+      index = 5,
+      sent = true,
+      source = "editor_context",
+      tag = "file"
+    },
+    content = "<attachment filepath=\"/Users/Oli/some_path/some_file.lua\">An example file</attachment>",
+    context = {
+      id = "<file>some_path/some_file.lua</file>",
+      path = "/Users/Oli/some_path/some_file.lua",
+    },
+    opts = {
+      visible = false
+    },
+    role = "user"
+  },
+  {
     _meta = {
       cycle = 1,
       id = 1141409506,

AGENTS.md

@@ -14,6 +14,7 @@ This is a Neovim plugin written in Lua, which allows developers to code with LLM
 - **Naming:** snake_case for files/functions, PascalCase for classes, underscore prefix for private functions
 - **Explicit names:** `pattern` not `pat`, `should_include` not `include_ok`
 - **Readable code:** names, variables, and control flow should read like clean English. Avoid generic names like `ctx` — use domain-specific names (`permission`, `request`, `source`)
+- **Plain language:** avoid jargon shortcuts in code, comments, commit messages, and chat. Don't say "no-op" — say what the code actually does ("returns unchanged", "does nothing", "skipped because already edited")
 - **Function params:** prefer a single table argument over positional args
 - **Error handling:** `pcall` + `log:error()`, return nil on failure
 - **Type annotations:** LuaCATS for public APIs. Keep doc blocks concise — one description line, params should be self-explanatory without inline comments

lua/codecompanion/config.lua

@@ -694,17 +694,24 @@ If you are providing code changes, use the insert_edit_into_file tool (if availa
       },
       opts = {
         context_management = {
-          trigger = 0.75, -- Compaction starts at 75% of the context window limit
-          enabled = function(adapter)
-            if adapter.type ~= "http" then
-              return false
-            end
-            -- Anthropic and OpenAI have their own server-side compaction
-            if adapter.vendor and (adapter.vendor == "anthropic" or adapter.vendor == "openai") then
-              return false
-            end
-            return true
-          end,
+          ---@type boolean|fun(adapter: CodeCompanion.HTTPAdapter|CodeCompanion.ACPAdapter): boolean
+          enabled = true,
+
+          editing = {
+            trigger = 0.65, -- 65% of the context window
+            exclude_tools = { "memory" }, -- tools whose result are never edited
+            keep_cycles = 3, -- preserve tool results from the last N cycles
+          },
+
+          compaction = {
+            trigger = 0.85, -- 85% of the context window
+
+            ---The adapter to use for compaction. Defaults to the current chat adapter
+            ---@type nil|string|{ name: string, model:string }
+            adapter = nil,
+
+            fallback_to_chat_adapter = false, -- on failure, retry with the chat adapter?
+          },
         },
 
         blank_prompt = "", -- The prompt to use when the user doesn't provide a prompt
@@ -1355,6 +1362,24 @@ M.setup = function(args)
     M.config.interactions.chat.editor_context = nil
   end
 
+  -- TODO: Deprecate in v20.0.0 and remove in v21.0.0
+  -- Legacy `context_management.trigger` migrates to `context_management.compaction.trigger`
+  local context_management = args.interactions
+    and args.interactions.chat
+    and args.interactions.chat.opts
+    and args.interactions.chat.opts.context_management
+  if context_management and context_management.trigger ~= nil then
+    vim.notify(
+      "[CodeCompanion] `context_management.trigger` is deprecated. Use `context_management.compaction.trigger` instead.",
+      vim.log.levels.WARN,
+      { title = "CodeCompanion" }
+    )
+    if not (context_management.compaction and context_management.compaction.trigger ~= nil) then
+      M.config.interactions.chat.opts.context_management.compaction.trigger = context_management.trigger
+    end
+    M.config.interactions.chat.opts.context_management.trigger = nil
+  end
+
   M.config.interactions.chat.keymaps = remove_disabled_keymaps(M.config.interactions.chat.keymaps)
   M.config.interactions.cli.keymaps = remove_disabled_keymaps(M.config.interactions.cli.keymaps)
   M.config.interactions.inline.keymaps = remove_disabled_keymaps(M.config.interactions.inline.keymaps)

lua/codecompanion/interactions/chat/buffer_diffs.lua

@@ -11,7 +11,7 @@ local diff = vim.text.diff or vim.diff
 
 ---@class CodeCompanion.BufferDiffs
 ---@field buffers table<number, CodeCompanion.BufferDiffs.State> Map of buffer numbers to their states
----@field augroup integer The autocmd group ID
+---@field augroup number The autocmd group ID
 ---@field sync fun(self: CodeCompanion.BufferDiffs, bufnr: number): nil Start syncing a buffer
 ---@field unsync fun(self: CodeCompanion.BufferDiffs, bufnr: number): nil Stop syncing a buffer
 ---@field get_changes fun(self: CodeCompanion.BufferDiffs, bufnr: number): boolean, table