Failed deploy explainer
By Toolspoke
Give it a failed Vercel deploy and it finds the first real error in the build log, says whose it is, and posts a fix to Slack.
Needs a Toolspoke account. You choose which project it installs into.
- Vercel + Slack
- Required integrations
- Runs when you ask
- No schedule of its own
- Post
- What its last step does
- Nothing destructive
- 0 of 22 actions in its tools
On this page
The short version
- What it is
- A ready-made Toolspoke agent that explains why a Vercel deploy failed and what to do about it.
- What you give it
- A deployment link or id, a project name, or "the latest failed one".
- What it reads
- The deployment, its build log, the last good deploy on the same branch, and the project's settings and variable names.
- Where it posts
- One Slack channel, chosen when you set it up, or the one you name.
- What it answers
- The failing step, the first real error line, whether it is code, configuration or the platform, and the smallest fix.
- What it never does
- Redeploy, change an environment variable or domain, or print a variable's value.
- What you need
- A Toolspoke account, a Vercel token and a Slack workspace.
What Failed deploy explainer does
Failed deploy explainer is an AI agent that reads a failed Vercel build down to the first line that broke, says whether it is the code, the project's configuration or the platform, and posts the fix to Slack.
A failed deploy shows a red badge and a log of several hundred lines. The last line usually says "Command exited with 1", which is true and useless. The real error is forty lines up, and finding it takes the person who knows the build best.
Most failures fall into three kinds with different owners: a change in the code, a setting or environment variable on the project, or something on the platform that a retry fixes. Knowing which one it is decides who picks it up.
Failed deploy explainer reads the deployment and its log, finds the failing step and the first real error inside it, checks the last good deploy on the same branch, and posts a short answer: what failed, the line, whose it is and the smallest fix.
In practice, you ask and get one message:
- The failing step: install, build, checks or output
- The first real error line, quoted exactly
- Whether it is code, configuration or the platform
- The smallest fix, and the last commit that deployed cleanly
How it works
Failed deploy explainer works in four steps when you ask: it finds the deployment, reads the log, decides whose it is and posts one answer. All of it comes from the agent's written instructions, which you can read and edit after you install it.
Step 1: Find the deployment
From a link, a project, or the latest failed one across your team.
Step 2: Read the log
It finds the failing step and the first real error line.
Step 3: Decide whose it is
It checks the code change, the project settings and Vercel's error code.
Step 4: Post the answer
It posts the step, the line, whose it is and the fix.
It reads to the real line
It reads up to 500 log lines with deployment_logs, newest first. A line that says the command exited is a summary; it goes back to the compiler error, the failed test or the missing module that started it, and quotes that line.
It compares with the last good deploy
It finds the newest ready deployment on the same branch with list_deployments and names its commit, so the change between the good build and the bad one is clear.
It checks configuration without seeing secrets
When the error points at a setting, it reads the project with get_project and the variable names with list_env_vars. That action returns names and target environments, never values, so it can say "DATABASE_URL is not set for Preview" without knowing what it holds.
It redacts what the log printed
A build log can contain a key a script echoed by mistake. The agent is told to replace any line that looks like a key, token, password or connection string with [redacted]. The limits are listed under what it will never do.
What an answer looks like
An answer from Failed deploy explainer is a single Slack post. It names the deployment, the failing step and the error, says whose it is, and gives the smallest fix.
Quillmark
Channels
- # deploys
- # engineering
- # frontend
- # general
# deploys
storefront, branch feature/gift-cards, commit 9f3c2a1 by Nadia. Production build failed.
What failed
- Step: build, after install finished.
app/checkout/page.tsx(48,17): Type 'string | undefined' is not assignable to type 'string'.
Whose it is
- Code. The file changed in this commit. The last good deploy on this branch was commit 4b81d0e an hour earlier.
- Fix: handle the missing value on line 48, or give
giftCardCodea default.
Link
Open the deployment in Vercel for the full log.
- What failed
The step that failed and the first real error line, quoted exactly so it can be searched.
- Whose it is
Code, configuration or platform, with the evidence, the last good commit and the smallest fix.
- Link
A link to the deployment, for anyone who wants to read the full log.
When there is nothing to explain
If there is no failed deployment for what you named, it says so and stops. It does not go looking for an older failure you did not ask about.
If the logs have expired or cannot be read, it says so and gives what the deployment record shows: the error code and the step. It does not guess the cause from the step name.
Who uses Failed deploy explainer
Failed deploy explainer suits any team that ships on Vercel and wants a red deploy picked up by the right person quickly. The examples use made-up names.
A developer whose preview broke
Nadia Haddad pushed a branch and the preview failed. Instead of scrolling the log, she asked in Slack and had the line and the fix in under a minute.
A lead triaging production
Ben Carter gets pinged when production fails to deploy. The answer tells him whether to find the author, fix a setting or simply retry.
A designer who pushes copy changes
Yuki Tanaka edits content files and sometimes trips the build. The answer is plain enough to fix the typo herself.
A small agency with many projects
Ola Nwosu looks after fifteen client sites. "The latest failed one" finds it across the team without opening each project.
What Failed deploy explainer connects to
Failed deploy explainer connects to two tools: it reads Vercel and posts to Slack. You connect each one yourself, and Toolspoke stores the connection encrypted, so the agent never sees the credential.
Vercel
RequiredInspect projects, deployments, domains, and build logs.
Authentication: Access token
Slack
RequiredSearch conversations and send messages to your workspace.
Authentication: Bot token
| Tool | What Failed deploy explainer does | What it cannot do |
|---|---|---|
| Vercel | Reads deployments, build logs, project settings and variable names (list_projects, list_deployments, get_deployment, deployment_logs, get_project, list_env_vars). | Redeploy, promote, cancel or roll back a deployment, or read an environment variable's value: the connector has no action for any of them. It can create or overwrite an environment variable and attach a domain, and this agent's instructions forbid both. |
| Slack | Posts one message with send_message, to a channel. | Delete messages: the connector has no delete action. It can also edit the bot's messages, schedule messages and react, and the agent is told not to. |
That the Vercel connection cannot redeploy or read a variable's value is a property of the connector. That the agent leaves environment variables and domains alone is an instruction, not a lock. If you want a lock, switch off upsert_env_var and add_project_domain in your project. The access control guide explains how.
Build logs can contain whatever a script printed. The agent is told to redact anything that looks like a secret before it posts, and the message posted to Slack is stored in the activity log.
What Failed deploy explainer will never do
Failed deploy explainer is told never to redeploy, never to change an environment variable or domain, and never to print a variable's value. It explains, and a person fixes.
- Redeploy, promote, cancel or roll back a deployment.
- Create or change an environment variable with upsert_env_var, or add a domain with add_project_domain.
- Print an environment variable's value, or any line of the log that looks like a key, token, password or connection string.
- Guess.
Why it does not redeploy
A retry that happens to pass hides a flaky build, and a production redeploy is a release. Both are decisions for the person who asked. The Vercel connector has no redeploy action in any case.
What it keeps out of Slack
A deploy channel is read by more people than the Vercel project's settings are. It names a variable, never its value, and redacts secrets a log printed.
DATABASE_URL ([redacted]). Check the value set for Preview.Why you may still want a lock
The Vercel connection can overwrite an environment variable and attach a domain. The agent is told not to, but switching those actions off in your project makes it a lock.
If something goes wrong
If the logs cannot be read or have expired, say so and give what get_deployment shows: the error code and the step. If there is no failed deployment, say that and stop. If Slack cannot be written, return the answer in the run's result.
These are written into Failed deploy explainer's instructions. They guide the agent, but they are not a permission. What it is allowed to touch is set by the access you grant.
Failed deploy explainer reads Vercel and explains what it finds. Every redeploy and every change to the project stays with a person.
When Failed deploy explainer runs
Failed deploy explainer has no schedule. It runs when you ask it about a deployment, a project or the latest failure, and it stops when it has answered.
- You give it a link, a project or "the latest failed one".
- It reads one deployment and its log.
- It posts one answer.
- It changes nothing in Vercel.
Each run uses model credit from your workspace balance. A long log costs a little more, because there is more to read. The Vercel and Slack calls themselves are free.
Your copy is an ordinary agent in your project. You can run it from Toolspoke whenever you need it, and edit its instructions. The agent's page lists recent runs and their cost.
How to set up Failed deploy explainer
To get failed deploys explained, add Failed deploy explainer to a Toolspoke project, connect Vercel and Slack and choose the channel. It takes a few minutes.
Step 1: Create a Toolspoke account or sign in
Choose Use this agent. If you are new, you will be asked to sign up first, and you come straight back to this agent afterwards.
Step 2: Add it to a project
Pick the project it should live in. You get your own editable copy, and you can see the two tools it brings before anything connects.
Step 3: Connect Vercel
Create a Vercel access token scoped to the team that owns your projects, and paste it. It is stored encrypted and the agent never sees it.
Step 4: Connect Slack
Choose Sign in with Slack and approve the Toolspoke app. For a private channel, add the Toolspoke bot to it first.
Step 5: Name the channel
Name the channel answers go to in the instructions, and the Vercel team if you have more than one.
Step 6: Ask it about a failure
Give it a deployment link or say "the latest failed one" and read the answer in Slack.
Make Failed deploy explainer fit your team
Failed deploy explainer's instructions are plain English and you can edit them after you install it. Installing copies the agent, so your edits stay with your copy. Open the agent in Toolspoke and tell the builder what to change, and it rewrites the instructions.
Paste any sentence below into the builder chat, or say the same thing in your own words.
When I ask from a Slack thread, answer in that thread instead of the channel.
Answer in three lines: the error, whose it is and the fix.
For "the latest failed one", only look at production deployments.
Run every hour and explain any production deploy that failed since the last run.
This gives the agent a schedule, so the builder adds one. Each run then uses model credit.
Call configuration problems "settings" in the answer.
None of these edits needs more access or touches the Never rules. They change what Failed deploy explainer is told, not what the connections allow.
How it compares to other options
Failed deploy explainer beats the alternatives when you want the first real error and its owner in your team's channel, and loses to them when you need a fix applied for you.
| Compared on | Failed deploy explainer | Vercel's failure notification | Reading the build log | An AI coding assistant |
|---|---|---|---|---|
| Finds the first real error | Yes, quoted | No, a link | Yes, if you scroll | If you paste the log |
| Says whose it is | Code, config or platform | No | If you know the build | Often |
| Checks variable names | Yes, never values | No | In settings | No |
| Names the last good commit | Yes | No | If you look | No |
| Can redeploy | No, the connector cannot | No | You can | Depends on its access |
| Applies the fix | No, suggests it | No | You do | Yes, in your editor |
| Setup effort | Connect two accounts | None | None | Already in your editor |
An AI coding assistant is the better choice once you know the failure is in the code: it can change the file. Failed deploy explainer gets you to that point and tells you when the problem is not the code at all.
Reading the build log yourself is fine when you wrote the change and know the build. The agent helps most when someone else is looking at a failure they did not cause.
Frequently asked questions
Can Failed deploy explainer redeploy?
No. The Vercel connector has no action that redeploys, promotes, cancels or rolls back a deployment.
Can it change environment variables?
It is told never to. The Vercel connection can create or overwrite a variable and attach a domain, so if you want a lock, switch those actions off in your project (how access works).
Can it see my secrets?
The variable action returns names and target environments, never values. A build log can contain something a script printed, so the agent is told to redact anything that looks like a secret before it posts.
What does it need from me?
A deployment link or id, a project name, or "the latest failed one". If it cannot tell which project you meant, it lists them and asks.
What if the logs have expired?
It says so and gives what the deployment record shows, such as the error code and the step. It does not guess the cause.
Does it work with GitHub Actions or Netlify?
Not this agent, which reads Vercel. For GitHub Actions, see CI failure explainer.
Is Failed deploy explainer free?
It has no price of its own, and every Toolspoke plan includes agents. Tool calls cost nothing, but each run draws on your usage balance. Pricing has the details.
Get from red badge to fix faster
Connect Vercel and Slack, name the channel and ask it about your next failed deploy.