diff --git a/CHANGELOG.md b/CHANGELOG.md
index 72adff8..d0a69c4 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,10 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## 1.5.2 - 2026-03-09
+
+- Added the JiraClient, allowing us to create, search, comment on Jira tickets for support processes.
+
 ## 1.5.1 - 2026-02-05
 
 - Handles cases where `$callers` and `$ancestors` may not be pids to avoid crashing metric handler.
diff --git a/lib/zexbox/jira_client.ex b/lib/zexbox/jira_client.ex
new file mode 100644
index 0000000..7ad5075
--- /dev/null
+++ b/lib/zexbox/jira_client.ex
@@ -0,0 +1,193 @@
+defmodule Zexbox.JiraClient do
+  @moduledoc """
+  HTTP client for the Jira Cloud REST API v3.
+
+  Mirrors `Opsbox::JiraClient`. Authenticates with Basic auth using
+  `JIRA_USER_EMAIL_ADDRESS` and `JIRA_API_TOKEN` environment variables
+  (or `:jira_email` / `:jira_api_token` application config).
+
+  ## Configuration
+
+  ```elixir
+  config :zexbox,
+    jira_base_url: "https://your-org.atlassian.net",
+    jira_email: System.get_env("JIRA_USER_EMAIL_ADDRESS"),
+    jira_api_token: System.get_env("JIRA_API_TOKEN")
+  ```
+
+  All public functions return `{:ok, result}` or `{:error, reason}`.
+  """
+
+  @bug_fingerprint_field %{id: "customfield_13442", name: "Bug Fingerprint[Short text]"}
+  @zigl_team_field %{id: "customfield_10101", name: "ZIGL Team[Dropdown]"}
+
+  @doc "Returns the bug fingerprint custom field metadata."
+  @spec bug_fingerprint_field() :: %{id: String.t(), name: String.t()}
+  def bug_fingerprint_field, do: @bug_fingerprint_field
+
+  @doc "Returns the ZIGL team custom field metadata."
+  @spec zigl_team_field() :: %{id: String.t(), name: String.t()}
+  def zigl_team_field, do: @zigl_team_field
+
+  @doc """
+  Search for the latest issues matching a JQL query (max 50 results).
+
+  - `jql` – JQL query string.
+  - `project_key` – optional; prepends `project = KEY AND` to the JQL.
+
+  Returns `{:ok, [issue_map]}` where each map includes a `"url"` browse key,
+  or `{:error, reason}` on failure.
+  """
+  @spec search_latest_issues(String.t(), String.t() | nil) :: {:ok, [map()]} | {:error, term()}
+  def search_latest_issues(jql, project_key \\ nil) do
+    fetch_issues(build_query(jql, project_key))
+  end
+
+  @doc """
+  Create a new Jira issue.
+
+  - `project_key` – Jira project key (e.g. `"SS"`).
+  - `summary` – issue summary string.
+  - `description` – ADF map (already built; not converted).
+  - `issuetype` – issue type name (e.g. `"Bug"`).
+  - `priority` – priority name (e.g. `"High"`).
+  - `custom_fields` – optional map of custom field ID → value (string keys).
+
+  Returns `{:ok, issue_map}` with a `"url"` browse key added, or `{:error, reason}`.
+  """
+  @spec create_issue(String.t(), String.t(), map(), String.t(), String.t(), map()) ::
+          {:ok, map()} | {:error, term()}
+  def create_issue(project_key, summary, description, issuetype, priority, custom_fields \\ %{}) do
+    fields =
+      Map.merge(
+        %{
+          "project" => %{"key" => project_key},
+          "summary" => summary,
+          "description" => description,
+          "issuetype" => %{"name" => issuetype},
+          "priority" => %{"name" => priority}
+        },
+        custom_fields
+      )
+
+    post_issue(fields)
+  end
+
+  @doc """
+  Transition a Jira issue to a new status by name (case-insensitive match).
+
+  - `issue_key` – issue key (e.g. `"SS-42"`).
+  - `status_name` – target status name (e.g. `"To do"`).
+
+  Returns `{:ok, %{success: true, status: name}}` or `{:error, reason}`.
+  """
+  @spec transition_issue(String.t(), String.t()) :: {:ok, map()} | {:error, term()}
+  def transition_issue(issue_key, status_name) do
+    client = build_client()
+
+    with {:ok, data} <- jira_get(client, "/rest/api/3/issue/#{issue_key}/transitions"),
+         transitions = Map.get(data, "transitions", []),
+         {:ok, target} <- find_transition(transitions, status_name),
+         {:ok, _resp} <-
+           jira_post(client, "/rest/api/3/issue/#{issue_key}/transitions", %{
+             "transition" => %{"id" => target["id"]}
+           }) do
+      {:ok, %{success: true, status: get_in(target, ["to", "name"])}}
+    end
+  end
+
+  @doc """
+  Add a comment to an existing Jira issue.
+
+  - `issue_key` – issue key (e.g. `"SS-42"`).
+  - `comment` – ADF map for the comment body (already built; not converted).
+
+  Returns `{:ok, comment_map}` or `{:error, reason}`.
+  """
+  @spec add_comment(String.t(), map()) :: {:ok, map()} | {:error, term()}
+  def add_comment(issue_key, comment), do: post_comment(issue_key, comment)
+
+  # --- Private ---
+
+  defp build_query(jql, nil), do: jql
+  defp build_query(jql, project_key), do: "project = #{project_key} AND #{jql}"
+
+  defp fetch_issues(query) do
+    build_client()
+    |> jira_get("/rest/api/3/issue/search",
+      jql: query,
+      maxResults: 50,
+      fields: ["key", "id", "self", "status", "summary"]
+    )
+    |> attach_issue_urls()
+  end
+
+  defp post_issue(fields) do
+    build_client()
+    |> jira_post("/rest/api/3/issue", %{"fields" => fields})
+    |> attach_issue_url()
+  end
+
+  defp post_comment(issue_key, comment) do
+    build_client()
+    |> jira_post("/rest/api/3/issue/#{issue_key}/comment", %{"body" => comment})
+  end
+
+  defp attach_issue_urls({:ok, body}) do
+    issues = Map.get(body, "issues", [])
+    {:ok, Enum.map(issues, &Map.put(&1, "url", browse_url(&1["key"])))}
+  end
+
+  defp attach_issue_urls({:error, _reason} = err), do: err
+
+  defp attach_issue_url({:ok, result}),
+    do: {:ok, Map.put(result, "url", browse_url(result["key"]))}
+
+  defp attach_issue_url({:error, _reason} = err), do: err
+
+  defp browse_url(key), do: "#{config(:jira_base_url, nil)}/browse/#{key}"
+
+  defp find_transition(transitions, status_name) do
+    case Enum.find(transitions, &matches_status?(&1, status_name)) do
+      nil -> {:error, "Cannot transition to '#{status_name}'"}
+      target -> {:ok, target}
+    end
+  end
+
+  defp matches_status?(transition, status_name) do
+    to_name = get_in(transition, ["to", "name"]) |> to_string()
+    String.downcase(to_name) == String.downcase(status_name)
+  end
+
+  defp jira_get(client, path, params \\ []) do
+    Req.get(client, url: path, params: params)
+    |> handle_response()
+  end
+
+  defp jira_post(client, path, body) do
+    Req.post(client, url: path, json: body)
+    |> handle_response()
+  end
+
+  defp handle_response({:ok, %{status: status, body: body}}) when status in 200..299,
+    do: {:ok, body || %{}}
+
+  defp handle_response({:ok, %{status: status, body: body}}),
+    do: {:error, "HTTP #{status}: #{inspect(body)}"}
+
+  defp handle_response({:error, reason}),
+    do: {:error, inspect(reason)}
+
+  defp build_client do
+    email = config(:jira_email, System.get_env("JIRA_USER_EMAIL_ADDRESS", ""))
+    token = config(:jira_api_token, System.get_env("JIRA_API_TOKEN", ""))
+
+    Req.new(
+      base_url: config(:jira_base_url, nil),
+      auth: {:basic, "#{email}:#{token}"},
+      headers: [{"accept", "application/json"}]
+    )
+  end
+
+  defp config(key, default), do: Application.get_env(:zexbox, key, default)
+end
diff --git a/mix.exs b/mix.exs
index 5e5dcb2..4422d48 100644
--- a/mix.exs
+++ b/mix.exs
@@ -4,7 +4,7 @@ defmodule Zexbox.MixProject do
   def project do
     [
       app: :zexbox,
-      version: "1.5.1",
+      version: "1.5.2",
       elixir: "~> 1.14",
       start_permanent: Mix.env() == :prod,
       dialyzer: [plt_add_apps: [:mix, :ex_unit]],
@@ -40,6 +40,7 @@ defmodule Zexbox.MixProject do
       {:ldclient, "~> 3.8.0", hex: :launchdarkly_server_sdk},
       {:mix_audit, "~> 2.0", only: [:dev, :test], runtime: false},
       {:mock, "~> 0.3.0", only: :test},
+      {:req, "~> 0.5"},
       {:sobelow, "~> 0.8", only: [:dev, :test]},
       {:telemetry, "~> 1.3"}
     ]
diff --git a/mix.lock b/mix.lock
index f3472fc..c7e589d 100644
--- a/mix.lock
+++ b/mix.lock
@@ -11,8 +11,10 @@
   "erlex": {:hex, :erlex, "0.2.7", "810e8725f96ab74d17aac676e748627a07bc87eb950d2b83acd29dc047a30595", [:mix], [], "hexpm", "3ed95f79d1a844c3f6bf0cea61e0d5612a42ce56da9c03f01df538685365efb0"},
   "ex_doc": {:hex, :ex_doc, "0.35.1", "de804c590d3df2d9d5b8aec77d758b00c814b356119b3d4455e4b8a8687aecaf", [:mix], [{:earmark_parser, "~> 1.4.39", [hex: :earmark_parser, repo: "hexpm", optional: false]}, {:makeup_c, ">= 0.1.0", [hex: :makeup_c, repo: "hexpm", optional: true]}, {:makeup_elixir, "~> 0.14 or ~> 1.0", [hex: :makeup_elixir, repo: "hexpm", optional: false]}, {:makeup_erlang, "~> 0.1 or ~> 1.0", [hex: :makeup_erlang, repo: "hexpm", optional: false]}, {:makeup_html, ">= 0.1.0", [hex: :makeup_html, repo: "hexpm", optional: true]}], "hexpm", "2121c6402c8d44b05622677b761371a759143b958c6c19f6558ff64d0aed40df"},
   "file_system": {:hex, :file_system, "1.1.0", "08d232062284546c6c34426997dd7ef6ec9f8bbd090eb91780283c9016840e8f", [:mix], [], "hexpm", "bfcf81244f416871f2a2e15c1b515287faa5db9c6bcf290222206d120b3d43f6"},
+  "finch": {:hex, :finch, "0.21.0", "b1c3b2d48af02d0c66d2a9ebfb5622be5c5ecd62937cf79a88a7f98d48a8290c", [:mix], [{:mime, "~> 1.0 or ~> 2.0", [hex: :mime, repo: "hexpm", optional: false]}, {:mint, "~> 1.6.2 or ~> 1.7", [hex: :mint, repo: "hexpm", optional: false]}, {:nimble_options, "~> 0.4 or ~> 1.0", [hex: :nimble_options, repo: "hexpm", optional: false]}, {:nimble_pool, "~> 1.1", [hex: :nimble_pool, repo: "hexpm", optional: false]}, {:telemetry, "~> 0.4 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "87dc6e169794cb2570f75841a19da99cfde834249568f2a5b121b809588a4377"},
   "gun": {:hex, :gun, "2.2.0", "b8f6b7d417e277d4c2b0dc3c07dfdf892447b087f1cc1caff9c0f556b884e33d", [:make, :rebar3], [{:cowlib, ">= 2.15.0 and < 3.0.0", [hex: :cowlib, repo: "hexpm", optional: false]}], "hexpm", "76022700c64287feb4df93a1795cff6741b83fb37415c40c34c38d2a4645261a"},
   "hackney": {:hex, :hackney, "1.25.0", "390e9b83f31e5b325b9f43b76e1a785cbdb69b5b6cd4e079aa67835ded046867", [:rebar3], [{:certifi, "~> 2.15.0", [hex: :certifi, repo: "hexpm", optional: false]}, {:idna, "~> 6.1.0", [hex: :idna, repo: "hexpm", optional: false]}, {:metrics, "~> 1.0.0", [hex: :metrics, repo: "hexpm", optional: false]}, {:mimerl, "~> 1.4", [hex: :mimerl, repo: "hexpm", optional: false]}, {:parse_trans, "3.4.1", [hex: :parse_trans, repo: "hexpm", optional: false]}, {:ssl_verify_fun, "~> 1.1.0", [hex: :ssl_verify_fun, repo: "hexpm", optional: false]}, {:unicode_util_compat, "~> 0.7.1", [hex: :unicode_util_compat, repo: "hexpm", optional: false]}], "hexpm", "7209bfd75fd1f42467211ff8f59ea74d6f2a9e81cbcee95a56711ee79fd6b1d4"},
+  "hpax": {:hex, :hpax, "1.0.3", "ed67ef51ad4df91e75cc6a1494f851850c0bd98ebc0be6e81b026e765ee535aa", [:mix], [], "hexpm", "8eab6e1cfa8d5918c2ce4ba43588e894af35dbd8e91e6e55c817bca5847df34a"},
   "idna": {:hex, :idna, "6.1.1", "8a63070e9f7d0c62eb9d9fcb360a7de382448200fbbd1b106cc96d3d8099df8d", [:rebar3], [{:unicode_util_compat, "~> 0.7.0", [hex: :unicode_util_compat, repo: "hexpm", optional: false]}], "hexpm", "92376eb7894412ed19ac475e4a86f7b413c1b9fbb5bd16dccd57934157944cea"},
   "influxql": {:hex, :influxql, "0.2.1", "71bfd5c0d81bf870f239baf3357bf5226b44fce16e1b9399ba1368203ca71245", [:mix], [], "hexpm", "75faf04960d6830ca0827869eaac1ba092655041c5e96deb2a588bafb601205c"},
   "instream": {:hex, :instream, "2.2.1", "8f27352b0490f3d43387d9dfb926e6235570ea8a52b3675347c98efd7863a86d", [:mix], [{:hackney, "~> 1.1", [hex: :hackney, repo: "hexpm", optional: false]}, {:influxql, "~> 0.2.0", [hex: :influxql, repo: "hexpm", optional: false]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: false]}, {:nimble_csv, "~> 1.0", [hex: :nimble_csv, repo: "hexpm", optional: false]}, {:poolboy, "~> 1.5", [hex: :poolboy, repo: "hexpm", optional: false]}], "hexpm", "e20c7cc24991fdd228fa93dc080ee7b9683f4c1509b3b718fdd385128d018c2a"},
@@ -25,14 +27,19 @@
   "makeup_erlang": {:hex, :makeup_erlang, "1.0.2", "03e1804074b3aa64d5fad7aa64601ed0fb395337b982d9bcf04029d68d51b6a7", [:mix], [{:makeup, "~> 1.0", [hex: :makeup, repo: "hexpm", optional: false]}], "hexpm", "af33ff7ef368d5893e4a267933e7744e46ce3cf1f61e2dccf53a111ed3aa3727"},
   "meck": {:hex, :meck, "0.9.2", "85ccbab053f1db86c7ca240e9fc718170ee5bda03810a6292b5306bf31bae5f5", [:rebar3], [], "hexpm", "81344f561357dc40a8344afa53767c32669153355b626ea9fcbc8da6b3045826"},
   "metrics": {:hex, :metrics, "1.0.1", "25f094dea2cda98213cecc3aeff09e940299d950904393b2a29d191c346a8486", [:rebar3], [], "hexpm", "69b09adddc4f74a40716ae54d140f93beb0fb8978d8636eaded0c31b6f099f16"},
+  "mime": {:hex, :mime, "2.0.7", "b8d739037be7cd402aee1ba0306edfdef982687ee7e9859bee6198c1e7e2f128", [:mix], [], "hexpm", "6171188e399ee16023ffc5b76ce445eb6d9672e2e241d2df6050f3c771e80ccd"},
   "mimerl": {:hex, :mimerl, "1.4.0", "3882a5ca67fbbe7117ba8947f27643557adec38fa2307490c4c4207624cb213b", [:rebar3], [], "hexpm", "13af15f9f68c65884ecca3a3891d50a7b57d82152792f3e19d88650aa126b144"},
+  "mint": {:hex, :mint, "1.7.1", "113fdb2b2f3b59e47c7955971854641c61f378549d73e829e1768de90fc1abf1", [:mix], [{:castore, "~> 0.1.0 or ~> 1.0", [hex: :castore, repo: "hexpm", optional: true]}, {:hpax, "~> 0.1.1 or ~> 0.2.0 or ~> 1.0", [hex: :hpax, repo: "hexpm", optional: false]}], "hexpm", "fceba0a4d0f24301ddee3024ae116df1c3f4bb7a563a731f45fdfeb9d39a231b"},
   "mix_audit": {:hex, :mix_audit, "2.1.5", "c0f77cee6b4ef9d97e37772359a187a166c7a1e0e08b50edf5bf6959dfe5a016", [:make, :mix], [{:jason, "~> 1.4", [hex: :jason, repo: "hexpm", optional: false]}, {:yaml_elixir, "~> 2.11", [hex: :yaml_elixir, repo: "hexpm", optional: false]}], "hexpm", "87f9298e21da32f697af535475860dc1d3617a010e0b418d2ec6142bc8b42d69"},
   "mock": {:hex, :mock, "0.3.9", "10e44ad1f5962480c5c9b9fa779c6c63de9bd31997c8e04a853ec990a9d841af", [:mix], [{:meck, "~> 0.9.2", [hex: :meck, repo: "hexpm", optional: false]}], "hexpm", "9e1b244c4ca2551bb17bb8415eed89e40ee1308e0fbaed0a4fdfe3ec8a4adbd3"},
   "nimble_csv": {:hex, :nimble_csv, "1.3.0", "b7f998dc62b222bce9596e46f028c7a5af04cb5dde6df2ea197c583227c54971", [:mix], [], "hexpm", "41ccdc18f7c8f8bb06e84164fc51635321e80d5a3b450761c4997d620925d619"},
+  "nimble_options": {:hex, :nimble_options, "1.1.1", "e3a492d54d85fc3fd7c5baf411d9d2852922f66e69476317787a7b2bb000a61b", [:mix], [], "hexpm", "821b2470ca9442c4b6984882fe9bb0389371b8ddec4d45a9504f00a66f650b44"},
   "nimble_parsec": {:hex, :nimble_parsec, "1.4.2", "8efba0122db06df95bfaa78f791344a89352ba04baedd3849593bfce4d0dc1c6", [:mix], [], "hexpm", "4b21398942dda052b403bbe1da991ccd03a053668d147d53fb8c4e0efe09c973"},
+  "nimble_pool": {:hex, :nimble_pool, "1.1.0", "bf9c29fbdcba3564a8b800d1eeb5a3c58f36e1e11d7b7fb2e084a643f645f06b", [:mix], [], "hexpm", "af2e4e6b34197db81f7aad230c1118eac993acc0dae6bc83bac0126d4ae0813a"},
   "parse_trans": {:hex, :parse_trans, "3.4.1", "6e6aa8167cb44cc8f39441d05193be6e6f4e7c2946cb2759f015f8c56b76e5ff", [:rebar3], [], "hexpm", "620a406ce75dada827b82e453c19cf06776be266f5a67cff34e1ef2cbb60e49a"},
   "poolboy": {:hex, :poolboy, "1.5.2", "392b007a1693a64540cead79830443abf5762f5d30cf50bc95cb2c1aaafa006b", [:rebar3], [], "hexpm", "dad79704ce5440f3d5a3681c8590b9dc25d1a561e8f5a9c995281012860901e3"},
   "quickrand": {:hex, :quickrand, "2.0.7", "d2bd76676a446e6a058d678444b7fda1387b813710d1af6d6e29bb92186c8820", [:rebar3], [], "hexpm", "b8acbf89a224bc217c3070ca8bebc6eb236dbe7f9767993b274084ea044d35f0"},
+  "req": {:hex, :req, "0.5.17", "0096ddd5b0ed6f576a03dde4b158a0c727215b15d2795e59e0916c6971066ede", [:mix], [{:brotli, "~> 0.3.1", [hex: :brotli, repo: "hexpm", optional: true]}, {:ezstd, "~> 1.0", [hex: :ezstd, repo: "hexpm", optional: true]}, {:finch, "~> 0.17", [hex: :finch, repo: "hexpm", optional: false]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: false]}, {:mime, "~> 2.0.6 or ~> 2.1", [hex: :mime, repo: "hexpm", optional: false]}, {:nimble_csv, "~> 1.0", [hex: :nimble_csv, repo: "hexpm", optional: true]}, {:plug, "~> 1.0", [hex: :plug, repo: "hexpm", optional: true]}], "hexpm", "0b8bc6ffdfebbc07968e59d3ff96d52f2202d0536f10fef4dc11dc02a2a43e39"},
   "shotgun": {:hex, :shotgun, "1.2.1", "a720063b49a763a97b245cc1ab6ee34e0e50d1ef61858e080db8e3b0dcd31af2", [:rebar3], [{:gun, "2.2.0", [hex: :gun, repo: "hexpm", optional: false]}], "hexpm", "a5ed7a1ff851419a70e292c4e2649c4d2c633141eb9a3432a4896c72b6d3f212"},
   "sobelow": {:hex, :sobelow, "0.14.0", "dd82aae8f72503f924fe9dd97ffe4ca694d2f17ec463dcfd365987c9752af6ee", [:mix], [{:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: false]}], "hexpm", "7ecf91e298acfd9b24f5d761f19e8f6e6ac585b9387fb6301023f1f2cd5eed5f"},
   "ssl_verify_fun": {:hex, :ssl_verify_fun, "1.1.7", "354c321cf377240c7b8716899e182ce4890c5938111a1296add3ec74cf1715df", [:make, :mix, :rebar3], [], "hexpm", "fe4c190e8f37401d30167c8c405eda19469f34577987c76dde613e838bbc67f8"},
diff --git a/test/zexbox/jira_client_test.exs b/test/zexbox/jira_client_test.exs
new file mode 100644
index 0000000..4936ab7
--- /dev/null
+++ b/test/zexbox/jira_client_test.exs
@@ -0,0 +1,186 @@
+defmodule Zexbox.JiraClientTest do
+  use ExUnit.Case
+  import Mock
+  alias Zexbox.JiraClient
+
+  @base_url "https://zigroup.atlassian.net"
+
+  setup do
+    Application.put_env(:zexbox, :jira_base_url, @base_url)
+    Application.put_env(:zexbox, :jira_email, "test@example.com")
+    Application.put_env(:zexbox, :jira_api_token, "test-token")
+
+    on_exit(fn ->
+      Application.delete_env(:zexbox, :jira_base_url)
+      Application.delete_env(:zexbox, :jira_email)
+      Application.delete_env(:zexbox, :jira_api_token)
+    end)
+
+    :ok
+  end
+
+  describe "bug_fingerprint_field/0" do
+    test "returns the correct field metadata" do
+      assert %{id: "customfield_13442", name: "Bug Fingerprint[Short text]"} =
+               JiraClient.bug_fingerprint_field()
+    end
+  end
+
+  describe "zigl_team_field/0" do
+    test "returns the correct field metadata" do
+      assert %{id: "customfield_10101", name: "ZIGL Team[Dropdown]"} =
+               JiraClient.zigl_team_field()
+    end
+  end
+
+  describe "search_latest_issues/2" do
+    test_with_mock "returns issues with url keys added on success", Req,
+      new: fn _opts -> :mock_client end,
+      get: fn :mock_client, _opts ->
+        {:ok,
+         %{
+           status: 200,
+           body: %{
+             "issues" => [
+               %{
+                 "key" => "SS-1",
+                 "id" => "10001",
+                 "self" => "#{@base_url}/rest/api/3/issue/10001"
+               }
+             ]
+           }
+         }}
+      end do
+      assert {:ok, [issue]} = JiraClient.search_latest_issues("status = Open", "SS")
+      assert issue["key"] == "SS-1"
+      assert issue["url"] == "#{@base_url}/browse/SS-1"
+    end
+
+    test_with_mock "returns empty list when no issues found", Req,
+      new: fn _opts -> :mock_client end,
+      get: fn :mock_client, _opts ->
+        {:ok, %{status: 200, body: %{"issues" => []}}}
+      end do
+      assert {:ok, []} = JiraClient.search_latest_issues("status = Open")
+    end
+
+    test_with_mock "returns error on non-2xx response", Req,
+      new: fn _opts -> :mock_client end,
+      get: fn :mock_client, _opts ->
+        {:ok, %{status: 401, body: %{"message" => "Unauthorized"}}}
+      end do
+      assert {:error, reason} = JiraClient.search_latest_issues("status = Open")
+      assert reason =~ "HTTP 401"
+    end
+
+    test_with_mock "returns error on request failure", Req,
+      new: fn _opts -> :mock_client end,
+      get: fn :mock_client, _opts ->
+        {:error, %{reason: :econnrefused}}
+      end do
+      assert {:error, _reason} = JiraClient.search_latest_issues("status = Open")
+    end
+  end
+
+  describe "create_issue/6" do
+    test_with_mock "creates issue and adds url to result", Req,
+      new: fn _opts -> :mock_client end,
+      post: fn :mock_client, _opts ->
+        {:ok,
+         %{
+           status: 201,
+           body: %{
+             "key" => "SS-99",
+             "id" => "10099",
+             "self" => "#{@base_url}/rest/api/3/issue/10099"
+           }
+         }}
+      end do
+      assert {:ok, result} =
+               JiraClient.create_issue(
+                 "SS",
+                 "checkout: RuntimeError",
+                 %{version: 1, type: "doc", content: []},
+                 "Bug",
+                 "High",
+                 %{"customfield_13442" => "checkout::RuntimeError"}
+               )
+
+      assert result["key"] == "SS-99"
+      assert result["url"] == "#{@base_url}/browse/SS-99"
+    end
+
+    test_with_mock "returns error on non-2xx response", Req,
+      new: fn _opts -> :mock_client end,
+      post: fn :mock_client, _opts ->
+        {:ok, %{status: 400, body: %{"errorMessages" => ["Invalid project"]}}}
+      end do
+      assert {:error, reason} =
+               JiraClient.create_issue("INVALID", "test", %{}, "Bug", "High")
+
+      assert reason =~ "HTTP 400"
+    end
+  end
+
+  describe "transition_issue/2" do
+    test_with_mock "transitions issue to target status", Req,
+      new: fn _opts -> :mock_client end,
+      get: fn :mock_client, _opts ->
+        {:ok,
+         %{
+           status: 200,
+           body: %{
+             "transitions" => [
+               %{"id" => "11", "to" => %{"name" => "To do"}},
+               %{"id" => "21", "to" => %{"name" => "In Progress"}}
+             ]
+           }
+         }}
+      end,
+      post: fn :mock_client, opts ->
+        assert opts[:json] == %{"transition" => %{"id" => "11"}}
+        {:ok, %{status: 204, body: nil}}
+      end do
+      assert {:ok, %{success: true, status: "To do"}} =
+               JiraClient.transition_issue("SS-1", "To do")
+    end
+
+    test_with_mock "returns error when target status not found", Req,
+      new: fn _opts -> :mock_client end,
+      get: fn :mock_client, _opts ->
+        {:ok,
+         %{
+           status: 200,
+           body: %{"transitions" => [%{"id" => "11", "to" => %{"name" => "Done"}}]}
+         }}
+      end do
+      assert {:error, reason} = JiraClient.transition_issue("SS-1", "Nonexistent")
+      assert reason =~ "Cannot transition to"
+    end
+  end
+
+  describe "add_comment/2" do
+    test_with_mock "adds comment and returns the response", Req,
+      new: fn _opts -> :mock_client end,
+      post: fn :mock_client, _opts ->
+        {:ok,
+         %{
+           status: 201,
+           body: %{"id" => "30001", "body" => %{}, "author" => %{"displayName" => "Bot"}}
+         }}
+      end do
+      comment = %{version: 1, type: "doc", content: []}
+      assert {:ok, result} = JiraClient.add_comment("SS-42", comment)
+      assert result["id"] == "30001"
+    end
+
+    test_with_mock "returns error on non-2xx response", Req,
+      new: fn _opts -> :mock_client end,
+      post: fn :mock_client, _opts ->
+        {:ok, %{status: 404, body: %{"errorMessages" => ["Issue not found"]}}}
+      end do
+      assert {:error, reason} = JiraClient.add_comment("SS-999", %{})
+      assert reason =~ "HTTP 404"
+    end
+  end
+end