Add opencode model variant customization

README.org

@@ -1050,6 +1050,7 @@ always go to Evil modes if you need to with ~C-z~).
 | agent-shell-openai-default-session-mode-id    | Default Codex session mode ID.                                                  |
 | agent-shell-opencode-acp-command              | Command and parameters for the OpenCode client.                                 |
 | agent-shell-opencode-authentication           | Configuration for OpenCode authentication.                                      |
+| agent-shell-opencode-default-config-options   | Default OpenCode config options, applied at session start.                      |
 | agent-shell-opencode-default-model-id         | Default OpenCode model ID.                                                      |
 | agent-shell-opencode-default-session-mode-id  | Default OpenCode session mode ID.                                               |
 | agent-shell-opencode-environment              | Environment variables for the OpenCode client.                                  |

agent-shell-config.el

@@ -144,6 +144,26 @@ For example:
                   matches)
         (car matches))))
 
+(defun agent-shell--resolve-config-option (state option)
+  "Return the config option in STATE addressed by OPTION, or nil.
+
+OPTION is matched against advertised ids first, then ACP categories, so
+both what a shell lists under \"Available config options\" (\"effort\")
+and the spec's category names (\"thought_level\") reach the same option.
+Ids cast the wider net: an option outside the spec's categories, say
+\"fast\", is only addressable by id.
+
+For example, against an agent advertising an \"effort\" option
+categorized as \"thought_level\":
+
+  (agent-shell--resolve-config-option state \"effort\")
+  => \\='((:id . \"effort\") (:category . \"thought_level\") ...)
+
+  (agent-shell--resolve-config-option state \"thought_level\")
+  => \\='((:id . \"effort\") (:category . \"thought_level\") ...)"
+  (or (agent-shell--config-option-get :state state :id option)
+      (agent-shell--config-option-by-category state option)))
+
 (defun agent-shell--select-config-options (state)
   "Return selectable (type = \"select\") config options from STATE."
   (seq-filter (lambda (option)

agent-shell-opencode.el

@@ -80,6 +80,31 @@ when starting a new shell."
   :type '(choice (const nil) string)
   :group 'agent-shell)
 
+(defcustom agent-shell-opencode-default-config-options
+  nil
+  "Default OpenCode config options, applied at session start.
+
+An alist of (OPTION . VALUE).  Both are the ids listed under
+\"Available config options\" when starting a new shell, so whatever
+OpenCode advertises can be set here without further agent-shell
+changes.  OPTION also accepts the ACP category names (\"model\",
+\"mode\", \"thought_level\") for options carrying one.
+
+OpenCode exposes model variants (provider-specific reasoning effort)
+as its \"effort\" option:
+
+  (setq agent-shell-opencode-default-config-options
+        \\='((\"model\" . \"anthropic/claude-opus-4-5\")
+          (\"effort\" . \"high\")
+          (\"mode\" . \"plan\")))
+
+Options are applied in the order listed.  Order matters: OpenCode
+scopes the available efforts to the active model, so \"effort\" belongs
+after \"model\".  An option or value OpenCode does not offer is
+reported and skipped."
+  :type '(alist :key-type string :value-type string)
+  :group 'agent-shell)
+
 (defcustom agent-shell-opencode-default-session-mode-id
   nil
   "Default OpenCode session mode ID.
@@ -129,6 +154,7 @@ Returns an agent configuration alist using `agent-shell-make-agent-config'."
                    (agent-shell-opencode-make-client :buffer buffer))
    :default-model-id (lambda () agent-shell-opencode-default-model-id)
    :default-session-mode-id (lambda () agent-shell-opencode-default-session-mode-id)
+   :default-config-options (lambda () agent-shell-opencode-default-config-options)
    :install-instructions "See https://opencode.ai/docs for installation."))
 
 ;;;###autoload

agent-shell.el

@@ -710,6 +710,7 @@ Each element can be:
                                               authenticate-request-maker
                                               default-model-id
                                               default-session-mode-id
+                                              default-config-options
                                               session-meta
                                               mcp-servers
                                               notification-adapter
@@ -729,6 +730,17 @@ Keyword arguments:
 - AUTHENTICATE-REQUEST-MAKER: Function to create authentication requests
 - DEFAULT-MODEL-ID: Default model ID (function returning value).
 - DEFAULT-SESSION-MODE-ID: Default session mode ID (function returning value).
+- DEFAULT-CONFIG-OPTIONS: Default ACP session config options (function
+  returning an alist of (OPTION . VALUE), both strings).  OPTION is
+  matched against the ids the agent advertises, falling back to ACP
+  categories (\"model\", \"mode\", \"thought_level\").  The categories
+  \"model\" and \"mode\" additionally reach agents advertising no config
+  options, via the same legacy requests DEFAULT-MODEL-ID and
+  DEFAULT-SESSION-MODE-ID use.  Applied in the order listed, after
+  DEFAULT-MODEL-ID and DEFAULT-SESSION-MODE-ID, so an entry here wins
+  over either.  Order matters: options an agent scopes to the active
+  model (thought level, for example) must follow the option selecting
+  that model.
 - SESSION-META: Optional alist of agent-specific metadata sent as `_meta'
   with session-creating requests (`session/new', `session/load',
   `session/resume', and `session/fork').
@@ -751,6 +763,7 @@ Returns an alist with all specified values."
     (:authenticate-request-maker . ,authenticate-request-maker) ;; function
     (:default-model-id . ,default-model-id)                     ;; function
     (:default-session-mode-id . ,default-session-mode-id)       ;; function
+    (:default-config-options . ,default-config-options)         ;; function
     (:session-meta . ,session-meta)
     (:mcp-servers . ,mcp-servers)
     (:notification-adapter . ,notification-adapter)            ;; function
@@ -1189,6 +1202,7 @@ OUTGOING-REQUEST-DECORATOR (passed through to `acp-make-client')."
         (cons :authenticated nil)
         (cons :set-model nil)
         (cons :set-session-mode nil)
+        (cons :set-config-options nil)
         (cons :session (list (cons :id nil)
                              (cons :config-options nil)
                              (cons :model-id nil)
@@ -2252,6 +2266,16 @@ Flow:
             :on-mode-changed (lambda ()
                                (map-put! (agent-shell--state) :set-session-mode t)
                                (agent-shell--handle :command command :shell-buffer shell-buffer))))
+          ;; Send ACP requests to set default config options (optional)
+          ((and (map-nested-elt (agent-shell--state) '(:agent-config :default-config-options))
+                (funcall (map-nested-elt (agent-shell--state) '(:agent-config :default-config-options)))
+                (not (map-elt (agent-shell--state) :set-config-options)))
+           (agent-shell--set-default-config-options
+            :shell-buffer shell-buffer
+            :config-options (funcall (map-nested-elt (agent-shell--state) '(:agent-config :default-config-options)))
+            :on-options-set (lambda ()
+                              (map-put! (agent-shell--state) :set-config-options t)
+                              (agent-shell--handle :command command :shell-buffer shell-buffer))))
           ;; Initialization complete
           (t
            (agent-shell--emit-event :event 'init-finished)
@@ -4046,7 +4070,8 @@ For example, shut down ACP client."
     (map-put! (agent-shell--state) :initialized nil)
     (map-put! (agent-shell--state) :authenticated nil)
     (map-put! (agent-shell--state) :set-model nil)
-    (map-put! (agent-shell--state) :set-session-mode nil))
+    (map-put! (agent-shell--state) :set-session-mode nil)
+    (map-put! (agent-shell--state) :set-config-options nil))
   (agent-shell-heartbeat-stop
    :heartbeat (map-elt (agent-shell--state) :heartbeat)))
 
@@ -6070,6 +6095,7 @@ Initialization events (emitted in order):
   `init-session'        - ACP session created
   `init-model'          - Default model set (optional)
   `init-session-mode'   - Default session mode set (optional)
+  `init-config-options' - Default config options applied (optional)
   `session-list'        - Session list fetch initiated
   `session-prompt'      - About to prompt user for session selection
   `session-selected'    - Session chosen (new or existing)
@@ -6615,6 +6641,162 @@ Call ON-MODE-CHANGED on success."
      :on-failure (agent-shell--make-error-handler
                   :state (agent-shell--state) :shell-buffer shell-buffer))))
 
+(defun agent-shell--default-config-option-values (state option)
+  "Return the value ids STATE advertises for OPTION.
+
+The ACP categories \"model\" and \"mode\" read through the accessors
+that unify config options with the legacy `models'/`modes' session
+fields, so they cover agents advertising no config options at all.
+Returns nil when OPTION is unknown to STATE, or constrains nothing.
+
+For example:
+
+  (agent-shell--default-config-option-values state \"thought_level\")
+  => \\='(\"low\" \"high\" \"max\")"
+  (pcase option
+    ("model" (seq-map (lambda (model)
+                        (map-elt model :model-id))
+                      (agent-shell--get-available-models state)))
+    ("mode" (seq-map (lambda (mode)
+                       (map-elt mode :id))
+                     (agent-shell--get-available-modes state)))
+    (_ (seq-map (lambda (value)
+                  (map-elt value :value))
+                (map-elt (agent-shell--resolve-config-option state option) :options)))))
+
+(defun agent-shell--default-config-option-addressable-p (state option)
+  "Return non-nil when STATE can be asked to set OPTION.
+
+\"model\" and \"mode\" are always addressable: agents advertising no
+config options still answer the legacy `session/set_model' and
+`session/set_mode' requests.  Any other OPTION has to resolve to an
+advertised config option."
+  (or (member option '("model" "mode"))
+      (agent-shell--resolve-config-option state option)))
+
+(defun agent-shell--default-config-option-settable-p (state option value)
+  "Return non-nil when STATE can be asked to set OPTION to VALUE.
+
+An option enumerating no values (a free-form string option, or one an
+agent only exposes over the legacy requests) accepts any VALUE."
+  (and (agent-shell--default-config-option-addressable-p state option)
+       (if-let* ((values (agent-shell--default-config-option-values state option)))
+           (member value values)
+         t)))
+
+(defun agent-shell--default-config-option-skip-reason (state option)
+  "Explain why OPTION could not be set in STATE.
+
+Names the ids the agent does offer, since agents advertise options
+conditionally and scope their values to the active model.
+
+For example:
+
+  (agent-shell--default-config-option-skip-reason state \"effort\")
+  => \"agent offers low, high, max\"
+
+  (agent-shell--default-config-option-skip-reason state \"fast\")
+  => \"agent advertises no fast option\""
+  (if-let* (((agent-shell--default-config-option-addressable-p state option))
+            (values (agent-shell--default-config-option-values state option)))
+      (format "agent offers %s" (string-join values ", "))
+    (format "agent advertises no %s option" option)))
+
+(cl-defun agent-shell--set-default-config-options (&key shell-buffer config-options (first t) on-options-set)
+  "Apply CONFIG-OPTIONS in SHELL-BUFFER, one at a time, in order.
+
+CONFIG-OPTIONS is an alist of (OPTION . VALUE), as described in
+`agent-shell-make-agent-config'.  Applying them in sequence (rather
+than concurrently) lets an earlier entry determine what a later one can
+choose from, since agents re-advertise their options on every change.
+
+FIRST tracks whether the next entry opens the progress report, and is
+managed by the recursion.
+
+Call ON-OPTIONS-SET once the list is exhausted."
+  (if-let* ((entry (car config-options)))
+      (agent-shell--set-default-config-option
+       :shell-buffer shell-buffer
+       :option (car entry)
+       :value (cdr entry)
+       :first first
+       :on-option-set (lambda ()
+                        (agent-shell--set-default-config-options
+                         :shell-buffer shell-buffer
+                         :config-options (cdr config-options)
+                         :first nil
+                         :on-options-set on-options-set)))
+    (agent-shell--emit-event :event 'init-config-options)
+    (when on-options-set
+      (funcall on-options-set))))
+
+(cl-defun agent-shell--set-default-config-option (&key shell-buffer option value first on-option-set)
+  "Set config OPTION to VALUE in SHELL-BUFFER, then call ON-OPTION-SET.
+
+Agents advertise options conditionally (thought levels only for models
+supporting them, for example) and scope values to the active model, so
+an unknown option or value is reported and skipped rather than
+aborting initialization.
+
+FIRST reports this as the opening line of the shared progress block,
+which later entries append their own line to."
+  (when (map-nested-elt (agent-shell--state) '(:session :id))
+    (with-current-buffer (map-elt agent-shell--state :buffer)
+      (agent-shell--update-bootstrapping-fragment
+       :state (agent-shell--state)
+       :block-id "set-config-options"
+       :label-left (propertize "Setting config options" 'font-lock-face 'agent-shell-section-heading)
+       :body (format "%s%s: requesting %s..." (if first "" "\n") option value)
+       :append t))
+    (if (agent-shell--default-config-option-settable-p (agent-shell--state) option value)
+        (agent-shell--send-default-config-option
+         :shell-buffer shell-buffer
+         :option option
+         :value value
+         :on-sent (lambda ()
+                    (agent-shell--update-bootstrapping-fragment
+                     :state (agent-shell--state)
+                     :block-id "set-config-options"
+                     :body " done"
+                     :append t)
+                    (when on-option-set
+                      (funcall on-option-set))))
+      (agent-shell--update-bootstrapping-fragment
+       :state (agent-shell--state)
+       :block-id "set-config-options"
+       :body (format " skipped (%s)"
+                     (agent-shell--default-config-option-skip-reason (agent-shell--state) option))
+       :append t)
+      (when on-option-set
+        (funcall on-option-set)))))
+
+(cl-defun agent-shell--send-default-config-option (&key shell-buffer option value on-sent)
+  "Ask the agent to set OPTION to VALUE, then call ON-SENT.
+
+The ACP categories \"model\" and \"mode\" route through the setters
+owning their legacy fallbacks, so an agent advertising no config
+options is still reachable over `session/set_model' and
+`session/set_mode'.  Any other OPTION resolves to an advertised
+config option and goes out as `session/set_config_option'.
+
+SHELL-BUFFER is where a rejected request reports its error."
+  (let ((on-failure (agent-shell--make-error-handler
+                     :state (agent-shell--state) :shell-buffer shell-buffer)))
+    (pcase option
+      ("model" (agent-shell--config-option-set-model-id
+                :model-id value
+                :on-success on-sent
+                :on-failure on-failure))
+      ("mode" (agent-shell--config-option-set-mode-id
+               :mode-id value
+               :on-success on-sent
+               :on-failure on-failure))
+      (_ (agent-shell--set-session-config-option
+          :config-id (map-elt (agent-shell--resolve-config-option (agent-shell--state) option) :id)
+          :value value
+          :on-success on-sent
+          :on-failure on-failure)))))
+
 (cl-defun agent-shell--initiate-session (&key shell-buffer on-session-init)
   "Initiate ACP session creation with SHELL-BUFFER.
 
@@ -6937,7 +7119,15 @@ overwrites an existing fragment with equivalent content."
      :block-id "set-session-mode"
      :label-left (propertize "Setting session mode"
                              'font-lock-face 'agent-shell-section-heading)
-     :body (format "Requesting %s..." mode-id))))
+     :body (format "Requesting %s..." mode-id)))
+  (when-let* ((options-fn (map-nested-elt state '(:agent-config :default-config-options)))
+              ((funcall options-fn))
+              ((not (map-elt state :set-config-options))))
+    (agent-shell--update-bootstrapping-fragment
+     :state state
+     :block-id "set-config-options"
+     :label-left (propertize "Setting config options"
+                             'font-lock-face 'agent-shell-section-heading))))
 
 (defun agent-shell--display-session-options ()
   "Display available session options during bootstrapping."

tests/agent-shell-opencode-tests.el

@@ -0,0 +1,47 @@
+;;; agent-shell-opencode-tests.el --- Tests for agent-shell-opencode -*- lexical-binding: t; -*-
+
+(require 'ert)
+(require 'agent-shell)
+(require 'agent-shell-opencode)
+
+;;; Code:
+
+(ert-deftest agent-shell-opencode-default-model-id-test ()
+  "Test that OpenCode config exposes default model id."
+  (let ((default-model-id-fn
+         (map-elt (agent-shell-opencode-make-agent-config) :default-model-id)))
+
+    (let ((agent-shell-opencode-default-model-id nil))
+      (should (null (funcall default-model-id-fn))))
+
+    (let ((agent-shell-opencode-default-model-id "anthropic/claude-opus-4-5"))
+      (should (string= (funcall default-model-id-fn) "anthropic/claude-opus-4-5")))))
+
+(ert-deftest agent-shell-opencode-default-config-options-test ()
+  "Test that OpenCode config exposes default config options."
+  (let ((default-config-options-fn
+         (map-elt (agent-shell-opencode-make-agent-config) :default-config-options)))
+
+    (let ((agent-shell-opencode-default-config-options nil))
+      (should (null (funcall default-config-options-fn))))
+
+    (let ((agent-shell-opencode-default-config-options
+           '(("model" . "anthropic/claude-opus-4-5")
+             ("effort" . "high"))))
+      (should (equal (funcall default-config-options-fn)
+                     '(("model" . "anthropic/claude-opus-4-5")
+                       ("effort" . "high")))))))
+
+(ert-deftest agent-shell-opencode-default-session-mode-id-test ()
+  "Test that OpenCode config exposes default session mode id."
+  (let ((default-session-mode-id-fn
+         (map-elt (agent-shell-opencode-make-agent-config) :default-session-mode-id)))
+
+    (let ((agent-shell-opencode-default-session-mode-id nil))
+      (should (null (funcall default-session-mode-id-fn))))
+
+    (let ((agent-shell-opencode-default-session-mode-id "plan"))
+      (should (string= (funcall default-session-mode-id-fn) "plan")))))
+
+(provide 'agent-shell-opencode-tests)
+;;; agent-shell-opencode-tests.el ends here