feat(issue): add --description option to lc issue update (#141)

## Summary

- Adds `lc issue update --description TEXT` (short: `-d TEXT`) to update
an issue's body text via Linear's `issueUpdate` mutation
- Supports `--description -` to open an editor (consistent with `issue
create` and other long-form inputs)
- Follows existing update-option precedence order (applied after
`--project`, before the comment-only fallback)
- Preserves multiline Markdown descriptions without truncation or
newline loss (handled by `WhatFor.description_for/1`)

## Changes

- `app/lib/linear_cli/linear/issue.ex`: New `update :update_description`
Ash action + `LinearCli.Linear.Issue.Update.UpdateDescription`
ManualUpdate module
- `app/lib/linear_cli/linear.ex`: New `update_issue_description/2`
domain code interface
- `app/lib/linear_cli/cli/issue_helpers.ex`: New `update_description/2`
helper + `:description` clause in `dispatch_update/2`
- `app/lib/linear_cli/cli/commands.ex`: Pass `description:` in
`issue_update/1`'s `update_opts` (via `Map.get` to handle partial option
maps in tests)
- `app/lib/linear_cli/cli.ex`: `--description` / `-d` option on `issue
update` subcommand

## Test plan

- [ ] 2 new action-layer tests for `update_issue_description/2` in
`issue_test.exs`
- [ ] 3 new helper tests for `update_description/2` and
`dispatch_update` in `issue_helpers_test.exs`
- [ ] 2 new CLI integration tests for `--description` and `-d` in
`issue_commands_test.exs`
- [ ] All 7 new tests pass; pre-existing `LinearCli.GitTest` environment
failures are unchanged

Fixes
https://linear.app/cryptokairos/issue/CRY-53/support-updating-issue-descriptions

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: bougyman

app/lib/linear_cli/cli.ex

@@ -661,6 +661,11 @@ defmodule LinearCli.CLI do
                   long: "--comment",
                   help: "Comment to add to the issue. - open an editor"
                 ],
+                description: [
+                  short: "-d",
+                  long: "--description",
+                  help: "Update the issue description. - to open an editor"
+                ],
                 project: [
                   short: "-p",
                   long: "--project",

app/lib/linear_cli/cli/commands.ex

@@ -457,6 +457,7 @@ defmodule LinearCli.CLI.Commands do
            Linear.issues(%{ids: Enum.map(issue_ids, &IssueHelpers.expand_issue_id/1)}) do
       update_opts = [
         comment: options.comment,
+        description: Map.get(options, :description),
         project: options.project,
         cancel: flags.cancel,
         close: flags.close,

app/lib/linear_cli/cli/issue_helpers.ex

@@ -301,6 +301,26 @@ defmodule LinearCli.CLI.IssueHelpers do
     end
   end
 
+  @doc """
+  Updates `issue`'s description to `description_input`, resolving it (asking,
+  or opening an editor, if not already given - via
+  `LinearCli.CLI.WhatFor.description_for/1`) first.
+  """
+  @spec update_description(%Linear.Issue{}, String.t() | nil) ::
+          {:ok, %Linear.Issue{}} | {:error, term()}
+  def update_description(issue, description_input) do
+    description = WhatFor.description_for(description_input)
+
+    case Linear.update_issue_description(issue, description) do
+      {:ok, updated} ->
+        Prompt.ok("#{issue.identifier} description updated")
+        {:ok, updated}
+
+      {:error, reason} ->
+        {:error, reason}
+    end
+  end
+
   @doc """
   Dispatches an issue update per whichever of `opts`' keys is set, in Ruby's
   exact precedence order:
@@ -341,6 +361,7 @@ defmodule LinearCli.CLI.IssueHelpers do
       opts[:cancel] -> normalize(cancel_issue(issue, opts))
       opts[:pr] -> issue_pr(issue, opts)
       opts[:project] -> normalize(attach_project(issue, opts[:project]))
+      opts[:description] -> normalize(update_description(issue, opts[:description]))
       opts[:comment] -> :ok
       true -> no_action_taken()
     end

app/lib/linear_cli/linear.ex

@@ -37,6 +37,7 @@ defmodule LinearCli.Linear do
       define :attach_issue_to_project, action: :attach_to_project, args: [:project_id]
       define :close_issue, action: :close, args: [:state_id]
       define :set_issue_status, action: :set_status, args: [:state_id]
+      define :update_issue_description, action: :update_description, args: [:description]
     end
 
     resource LinearCli.Linear.Label do

app/lib/linear_cli/linear/issue.ex

@@ -53,6 +53,11 @@ defmodule LinearCli.Linear.Issue do
       argument :state_id, :string, allow_nil?: false
       manual LinearCli.Linear.Issue.Update.SetStatus
     end
+
+    update :update_description do
+      argument :description, :string, allow_nil?: false
+      manual LinearCli.Linear.Issue.Update.UpdateDescription
+    end
   end
 
   attributes do
@@ -378,3 +383,16 @@ defmodule LinearCli.Linear.Issue.Update.SetStatus do
     })
   end
 end
+
+defmodule LinearCli.Linear.Issue.Update.UpdateDescription do
+  @moduledoc false
+  use Ash.Resource.ManualUpdate
+
+  alias LinearCli.Linear.Issue
+
+  def update(changeset, _opts, _context) do
+    Issue.Update.run(changeset.data.identifier, %{
+      "description" => changeset.arguments.description
+    })
+  end
+end

app/test/linear_cli/cli/issue_commands_test.exs

@@ -970,6 +970,64 @@ defmodule LinearCli.CLI.IssueCommandsTest do
       assert output =~ "CRY-1 was closed"
     end
 
+    test "--description updates the issue description via the issueUpdate mutation" do
+      test_pid = self()
+
+      Req.Test.stub(LinearCli.Api, fn conn ->
+        {:ok, body, conn} = Plug.Conn.read_body(conn)
+        decoded = Jason.decode!(body)
+        query = decoded["query"]
+
+        cond do
+          String.contains?(query, "issue(id: $id)") ->
+            Req.Test.json(conn, %{"data" => %{"issue" => issue_map()}})
+
+          String.contains?(query, "issueUpdate") ->
+            send(test_pid, {:description, decoded["variables"]["input"]["description"]})
+            Req.Test.json(conn, issue_updated(%{"description" => "Updated body"}))
+
+          true ->
+            raise "no stub matched query: #{query}"
+        end
+      end)
+
+      output =
+        capture_io(fn ->
+          assert :ok =
+                   LinearCli.CLI.main([
+                     "issue",
+                     "update",
+                     "--description",
+                     "Updated body",
+                     "CRY-1"
+                   ])
+        end)
+
+      assert_received {:description, "Updated body"}
+      assert output =~ "CRY-1 description updated"
+    end
+
+    test "-d short flag also updates the issue description" do
+      stub_responses([
+        {"issue(id: $id)", %{"data" => %{"issue" => issue_map()}}},
+        {"issueUpdate", issue_updated(%{"description" => "Short flag body"})}
+      ])
+
+      output =
+        capture_io(fn ->
+          assert :ok =
+                   LinearCli.CLI.main([
+                     "issue",
+                     "update",
+                     "-d",
+                     "Short flag body",
+                     "CRY-1"
+                   ])
+        end)
+
+      assert output =~ "CRY-1 description updated"
+    end
+
     test "with no issue ids, exits 22 (Ruby: raise SmellsBad -> exit 22)" do
       test_pid = self()
       halt = fn code -> send(test_pid, {:halted, code}) end

app/test/linear_cli/cli/issue_helpers_test.exs

@@ -263,6 +263,26 @@ defmodule LinearCli.CLI.IssueHelpersTest do
     end
   end
 
+  describe "update_description/2" do
+    test "resolves and sends the description, printing a confirmation" do
+      stub_responses([{"issueUpdate", issue_updated(%{"description" => "New body"})}])
+
+      assert capture_io(fn ->
+               assert {:ok, %Issue{description: "New body"}} =
+                        IssueHelpers.update_description(issue(), "New body")
+             end) =~ "CRY-1 description updated"
+    end
+
+    test "propagates an API error without printing confirmation" do
+      stub_responses([{"issueUpdate", %{"errors" => [%{"message" => "boom"}]}}])
+
+      assert capture_io(fn ->
+               assert {:error, %Ash.Error.Invalid{}} =
+                        IssueHelpers.update_description(issue(), "New body")
+             end) == ""
+    end
+  end
+
   describe "attach_project/2 (Ruby: CLI::Issue#attach_project)" do
     test "resolves the project by name against the team's projects and attaches it" do
       stub_responses([
@@ -363,6 +383,17 @@ defmodule LinearCli.CLI.IssueHelpersTest do
       assert output =~ "CRY-1 was attached to Manhattan Rollout"
     end
 
+    test "with :description, updates the issue description" do
+      stub_responses([{"issueUpdate", issue_updated(%{"description" => "New body"})}])
+
+      output =
+        capture_io(fn ->
+          assert :ok = IssueHelpers.update_issue(issue(), description: "New body")
+        end)
+
+      assert output =~ "CRY-1 description updated"
+    end
+
     test "with only :comment, comments and stops without the 'no action taken' warning" do
       stub_responses([{"commentCreate", comment_created()}])
 

app/test/linear_cli/linear/issue_test.exs

@@ -376,4 +376,49 @@ defmodule LinearCli.Linear.IssueTest do
       assert {:error, %Ash.Error.Invalid{}} = Linear.close_issue(issue, "nope")
     end
   end
+
+  describe "update_issue_description/2" do
+    test "sends description and returns the issue refetched via full_fields" do
+      issue = struct!(LinearCli.Linear.Issue, id: "i1", identifier: "CRY-1")
+
+      Req.Test.stub(LinearCli.Api, fn conn ->
+        {:ok, body, conn} = Plug.Conn.read_body(conn)
+        %{"variables" => %{"id" => id, "input" => input}} = Jason.decode!(body)
+
+        assert id == "CRY-1"
+        assert input == %{"description" => "Updated body"}
+
+        Req.Test.json(conn, %{
+          "data" => %{
+            "issueUpdate" => %{
+              "issue" => %{
+                "id" => "i1",
+                "identifier" => "CRY-1",
+                "title" => "Fix it",
+                "branchName" => "cry-1-fix-it",
+                "description" => "Updated body",
+                "assignee" => nil,
+                "team" => %{"id" => "t1", "key" => "ENG", "name" => "Engineering"},
+                "comments" => %{"nodes" => []}
+              }
+            }
+          }
+        })
+      end)
+
+      assert {:ok, updated} = Linear.update_issue_description(issue, "Updated body")
+      assert updated.description == "Updated body"
+    end
+
+    test "surfaces a GraphQL error" do
+      issue = struct!(LinearCli.Linear.Issue, id: "i1", identifier: "CRY-1")
+
+      Req.Test.stub(LinearCli.Api, fn conn ->
+        Req.Test.json(conn, %{"errors" => [%{"message" => "unauthorized"}]})
+      end)
+
+      assert {:error, %Ash.Error.Invalid{}} =
+               Linear.update_issue_description(issue, "Updated body")
+    end
+  end
 end