diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,10 +5,19 @@
 The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/)
 and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.html).
 
-## 0.3.9 - 2026-01-06
+## [0.3.10] - 2026-10-13
 
 ### Added
 
+- `hci effect run --pretend-tag` and `--as-tag` for simulating effects as if on a specific git tag.
+   This sets `primaryRepo.tag` in the `herculesCI` arguments, useful for testing tag-conditional behavior such as publishing.
+
+   Also available in `hci effect eval` and `hci effect list`.
+
+## [0.3.9] - 2026-01-06
+
+### Added
+
 - `hci effect eval`: Evaluate an effect and print its derivation path.
 
 - `hci effect list`: List all effects in a `herculesCI` configuration.
@@ -17,162 +26,181 @@
 
 - `hci effect run`/`eval` now pass the `primaryRepo.owner` and `primaryRepo.name` fields correctly instead of `null`.
 
-## 0.3.8 - 2025-07-18
+## [0.3.8] - 2025-07-18
 
 ### Fixed
 
 - Interrupt signal handling is now more robust
 
-## 0.3.7 - 2024-02-12
+## [0.3.7] - 2024-02-12
 
 ### Fixed
 
- - `hci state` Commands are now more robust, retrying when HTTP requests fail
-
-## 0.3.6 - 2023-03-07
-
-### Fixed
+- `hci state` Commands are now more robust, retrying when HTTP requests fail
 
- - `hci effect run`: Attribute names with spaces, periods and/or quotes can now be specified on the command line.
+## [0.3.6] - 2023-03-07
 
 ### Added
 
- - `hci effect run --pretend-branch` and `--pretend-ref` can now be used to replace `--as-*`.
+- `hci effect run --pretend-branch` and `--pretend-ref` can now be used to replace `--as-*`.
    This command allows an effect to run locally for development, instead of on `hercules-ci-agent`.
 
    `--as-*` flags are still available, for those who don't want to switch right away, to remain compatible with outdated installations of `hci`.
 
- - `--version`
+- `--version`
 
-## 0.3.5 - 2022-12-29
+### Fixed
 
+- `hci effect run`: Attribute names with spaces, periods and/or quotes can now be specified on the command line.
+
+## [0.3.5] - 2022-12-29
+
 ### Fixed
 
- - Explain what to do when git's upstream HEAD is missing.
+- Explain what to do when git's upstream HEAD is missing.
 
- - Explicitly initialize nix on startup. This will prevent rare but obscure errors.
+- Explicitly initialize nix on startup. This will prevent rare but obscure errors.
 
 ### Changed
 
- - Unwrap some error messages for readability.
+- Unwrap some error messages for readability.
 
-## 0.3.4 - 2022-12-02
+## [0.3.4] - 2022-12-02
 
 ### Added
 
- - `hci state get --version INT` added, to retrieve a specific revision of a remote state file.
+- `hci state get --version INT` added, to retrieve a specific revision of a remote state file.
 
-## 0.3.3 - 2022-11-15
+## [0.3.3] - 2022-11-15
 
 ### Added
 
- - `hci effect run` can now run `onSchedule.<name>.*` effect attributes.
+- `hci effect run` can now run `onSchedule.<name>.*` effect attributes.
 
- - Basic support for the `GitToken` secret type. You may enter a personal access token
+- Basic support for the `GitToken` secret type. You may enter a personal access token
    by hand.
 
 ### Fixed
 
- - Fix a common error when an explicit upstream is missing but only one remote exists.
+- Fix a common error when an explicit upstream is missing but only one remote exists.
    This was sufficient data to determine the project context, and now it works.
 
-## 0.3.2 - 2022-06-21
+## [0.3.2] - 2022-06-21
 
 ### Added
 
- - Nix 2.9 support
+- Nix 2.9 support
 
-## 0.3.1 - 2022-05-17
+## [0.3.1] - 2022-05-17
 
 ### Added
 
- - `HERCULES_CI_SECRETS_JSON` can now be used to find the secrets
+- `HERCULES_CI_SECRETS_JSON` can now be used to find the secrets
    in an alternate location.
 
- - Other improvements for running in sandboxed environments, chiefly
+- Other improvements for running in sandboxed environments, chiefly
    [`hercules-ci-effects effectVMTest`](https://docs.hercules-ci.com/hercules-ci-effects/reference/nix-functions/effectvmtest/)
 
-## 0.3.0 - 2022-03-15
+## [0.3.0] - 2022-03-15
 
 ### Added
 
- - `hci secret echo` to assemble a secret and print it on stdout.
+- `hci secret echo` to assemble a secret and print it on stdout.
    Not unlike `hci secret add` but for people who don't have local
    secrets as part of their setup.
 
- - `hci secret add/echo --password` to ask a password on the terminal.
+- `hci secret add/echo --password` to ask a password on the terminal.
 
- - `hci secret add/echo` add a default `condition` to the secret.
+- `hci secret add/echo` add a default `condition` to the secret.
 
- - Parity with hercules-ci-agent 0.9.0: flake support, `onPush` jobs
+- Parity with hercules-ci-agent 0.9.0: flake support, `onPush` jobs
    in `hci effect run`.
 
 ### Fixed
 
- - Nix warnings don't pollute the shell completions anymore
+- Nix warnings don't pollute the shell completions anymore
 
-## 0.2.6 - 2022-03-09
+## [0.2.6] - 2022-03-09
 
 ### Added
 
- - Haskell `aeson` 2.0 support
+- Haskell `aeson` 2.0 support
 
-## 0.2.5 - 2022-03-07
+## [0.2.5] - 2022-03-07
 
 ### Added
 
- - `hci secret echo`: write secret data on stdout. A side-effect free version of `hci secret add`.
+- `hci secret echo`: write secret data on stdout. A side-effect free version of `hci secret add`.
 
- - `hci secret echo/add --password`: another safe way of inputting a secret field
+- `hci secret echo/add --password`: another safe way of inputting a secret field
 
-## 0.2.4 - 2021-11-17
+## [0.2.4] - 2021-11-17
 
 ### Added
 
- - Improved error message when git upstream is not found
+- Improved error message when git upstream is not found
 
 ### Changed
 
- - The flake packages and modules now link with Nix 2.4.
+- The flake packages and modules now link with Nix 2.4.
    Nix 2.3 support is still available via `packages.${system}.hercules-ci-cli-nix_2_3`, but will be removed in cli 0.3.x.
 
-## 0.2.3 - 2021-10-12
+## [0.2.3] - 2021-10-12
 
 ### Fixed
 
- - Remove a redundant API call that is not available using the Effect-provided token
+- Remove a redundant API call that is not available using the Effect-provided token
 
-## 0.2.2 - 2021-09-06
+## [0.2.2] - 2021-09-06
 
 ### Added
 
- - `hci lock` subcommands for optional cloud locks, to be used in conjunction with state, but not enforced.
+- `hci lock` subcommands for optional cloud locks, to be used in conjunction with state, but not enforced.
 
- - `hci` can now run in the effects sandbox inheriting the project's context. (hercules-ci-agent >= 0.8.3)
+- `hci` can now run in the effects sandbox inheriting the project's context. (hercules-ci-agent >= 0.8.3)
 
 ### Fixed
 
- - Interrupt handling
+- Interrupt handling
 
-## 0.2.1 - 2021-06-22
+## [0.2.1] - 2021-06-22
 
 ### Added
 
- - Compatibility with updated dependencies
+- Compatibility with updated dependencies
 
-## 0.2.0 - 2021-04-21
+## [0.2.0] - 2021-04-21
 
 ### Added
 
- - `hci secret add`: Add `--json-env` and `--string-env`: more secure alternative for literals
+- `hci secret add`: Add `--json-env` and `--string-env`: more secure alternative for literals
 
-### Changes
+### Changed
 
- - Remove `-h` and `--help` from tab completion and help text.
- - User-friendly error when `ci.nix` or similar can not be found.
+- Remove `-h` and `--help` from tab completion and help text.
+- User-friendly error when `ci.nix` or similar can not be found.
 
-## 0.1.0
+## [0.1.0] - 2021-03-07
 
 ### Added
 
- - First version of the `hci` command
+- First version of the `hci` command
+
+[0.2.0]: https://github.com/hercules-ci/hercules-ci-agent/compare/hercules-ci-cli-0.1.0...hercules-ci-cli-0.2.0
+[0.2.1]: https://github.com/hercules-ci/hercules-ci-agent/compare/hercules-ci-cli-0.2.0...hercules-ci-cli-0.2.1
+[0.2.2]: https://github.com/hercules-ci/hercules-ci-agent/compare/hercules-ci-cli-0.2.1...hercules-ci-cli-0.2.2
+[0.2.3]: https://github.com/hercules-ci/hercules-ci-agent/compare/hercules-ci-cli-0.2.2...hercules-ci-cli-0.2.3
+[0.2.4]: https://github.com/hercules-ci/hercules-ci-agent/compare/hercules-ci-cli-0.2.3...hercules-ci-cli-0.2.4
+[0.2.5]: https://github.com/hercules-ci/hercules-ci-agent/compare/hercules-ci-cli-0.2.4...hercules-ci-cli-0.2.5
+[0.2.6]: https://github.com/hercules-ci/hercules-ci-agent/compare/hercules-ci-cli-0.2.5...hercules-ci-cli-0.2.6
+[0.3.0]: https://github.com/hercules-ci/hercules-ci-agent/compare/hercules-ci-cli-0.2.6...hercules-ci-cli-0.3.0
+[0.3.1]: https://github.com/hercules-ci/hercules-ci-agent/compare/hercules-ci-cli-0.3.0...hercules-ci-cli-0.3.1
+[0.3.2]: https://github.com/hercules-ci/hercules-ci-agent/compare/hercules-ci-cli-0.3.1...hercules-ci-cli-0.3.2
+[0.3.3]: https://github.com/hercules-ci/hercules-ci-agent/compare/hercules-ci-cli-0.3.2...hercules-ci-cli-0.3.3
+[0.3.4]: https://github.com/hercules-ci/hercules-ci-agent/compare/hercules-ci-cli-0.3.3...hercules-ci-cli-0.3.4
+[0.3.5]: https://github.com/hercules-ci/hercules-ci-agent/compare/hercules-ci-cli-0.3.4...hercules-ci-cli-0.3.5
+[0.3.6]: https://github.com/hercules-ci/hercules-ci-agent/compare/hercules-ci-cli-0.3.5...hercules-ci-cli-0.3.6
+[0.3.7]: https://github.com/hercules-ci/hercules-ci-agent/compare/hercules-ci-cli-0.3.6...hercules-ci-cli-0.3.7
+[0.3.8]: https://github.com/hercules-ci/hercules-ci-agent/compare/hercules-ci-cli-0.3.7...hercules-ci-cli-0.3.8
+[0.3.9]: https://github.com/hercules-ci/hercules-ci-agent/compare/hercules-ci-cli-0.3.8...hercules-ci-cli-0.3.9
+[Unreleased]: https://github.com/hercules-ci/hercules-ci-agent/compare/stable...master
diff --git a/hercules-ci-cli.cabal b/hercules-ci-cli.cabal
--- a/hercules-ci-cli.cabal
+++ b/hercules-ci-cli.cabal
@@ -1,7 +1,7 @@
 cabal-version: 1.12
 
 name:           hercules-ci-cli
-version:        0.3.9
+version:        0.3.10
 synopsis:       The hci command for working with Hercules CI
 homepage:       https://docs.hercules-ci.com
 bug-reports:    https://github.com/hercules-ci/hercules-ci-agent/issues
diff --git a/src/Hercules/CLI/Effect.hs b/src/Hercules/CLI/Effect.hs
--- a/src/Hercules/CLI/Effect.hs
+++ b/src/Hercules/CLI/Effect.hs
@@ -24,7 +24,7 @@
 import Hercules.CLI.Client (HerculesClientEnv, HerculesClientToken, determineDefaultApiBaseUrl, projectsClient, retryOnFail)
 import Hercules.CLI.Common (runAuthenticatedOrDummy)
 import Hercules.CLI.Exception (exitMsg)
-import Hercules.CLI.Git (getAllBranches, getHypotheticalRefs)
+import Hercules.CLI.Git (getAllBranches, getAllTags, getHypotheticalRefs)
 import qualified Hercules.CLI.Git as Git
 import Hercules.CLI.JSON (askPasswordWithKey)
 import Hercules.CLI.Nix (ciNixAttributeCompleter, computeRef, createHerculesCIArgs, resolveInputs, withNix)
@@ -336,13 +336,18 @@
   strOption (long "pretend-branch" <> metavar "BRANCH" <> help "Pretend we're on another git branch" <> completer (flatCompleter getAllBranches))
     <|> strOption (long "as-branch" <> metavar "BRANCH" <> help "Alias for --pretend-branch")
 
+asTagOption :: Optparse.Parser Text
+asTagOption =
+  strOption (long "pretend-tag" <> metavar "TAG" <> help "Pretend we're on another git tag" <> completer (flatCompleter getAllTags))
+    <|> strOption (long "as-tag" <> metavar "TAG" <> help "Alias for --pretend-tag")
+
 asRefOption :: Optparse.Parser Text
 asRefOption =
   strOption (long "pretend-ref" <> metavar "REF" <> help "Pretend we're on another git ref" <> completer (flatCompleter getHypotheticalRefs))
     <|> strOption (long "as-ref" <> metavar "REF" <> help "Alias for --pretend-ref")
 
 asRefOptions :: Optparse.Parser (Maybe Text)
-asRefOptions = optional (asRefOption <|> (("refs/heads/" <>) <$> asBranchOption))
+asRefOptions = optional (asRefOption <|> (("refs/heads/" <>) <$> asBranchOption) <|> (("refs/tags/" <>) <$> asTagOption))
 
 data ProjectData = ProjectData
   { pdProjectPath :: Maybe ProjectPath,
diff --git a/src/Hercules/CLI/Git.hs b/src/Hercules/CLI/Git.hs
--- a/src/Hercules/CLI/Git.hs
+++ b/src/Hercules/CLI/Git.hs
@@ -53,7 +53,7 @@
 getHypotheticalRefs :: IO [Text]
 getHypotheticalRefs = do
   refs <- getRefs
-  pure $ sort $ ordNub (refs <> map ("refs/heads/" <>) (allBranches refs))
+  pure $ sort $ ordNub (refs <> map ("refs/heads/" <>) (allBranches refs) <> map ("refs/tags/" <>) (allTags refs))
 
 allBranches :: [Text] -> [Text]
 allBranches = concatMap filterRef
@@ -64,6 +64,12 @@
 
 getAllBranches :: IO [Text]
 getAllBranches = getRefs <&> allBranches
+
+allTags :: [Text] -> [Text]
+allTags = mapMaybe (T.stripPrefix "refs/tags/")
+
+getAllTags :: IO [Text]
+getAllTags = getRefs <&> allTags
 
 getUpstreamURL :: IO Text
 getUpstreamURL = do
diff --git a/src/Hercules/CLI/Nix.hs b/src/Hercules/CLI/Nix.hs
--- a/src/Hercules/CLI/Nix.hs
+++ b/src/Hercules/CLI/Nix.hs
@@ -90,6 +90,9 @@
 refBranchToRef :: Maybe Text -> Maybe Text -> Maybe Text
 refBranchToRef ref branch = ref <|> (("refs/heads/" <>) <$> branch)
 
+refBranchTagToRef :: Maybe Text -> Maybe Text -> Maybe Text -> Maybe Text
+refBranchTagToRef ref branch tag = ref <|> (("refs/heads/" <>) <$> branch) <|> (("refs/tags/" <>) <$> tag)
+
 withNix :: (MonadUnliftIO m) => (Store -> Ptr EvalState -> m b) -> m b
 withNix f = do
   liftIO do
@@ -175,7 +178,8 @@
     ref <- do
       ref <- liftA2 (<|>) (scanOption "--as-ref") (scanOption "--pretend-ref")
       branch <- liftA2 (<|>) (scanOption "--as-branch") (scanOption "--pretend-branch")
-      pure $ refBranchToRef ref branch
+      tag <- liftA2 (<|>) (scanOption "--as-tag") (scanOption "--pretend-tag")
+      pure $ refBranchTagToRef ref branch tag
     projectMaybe <-
       scanOption "--project" <&> \maybeStr -> do
         s <- maybeStr