How to share context with an AI coding agent safely
A practical way to give an AI coding agent the prompt, task, board, or diagram context it needs without exposing an entire workspace or leaving a permanent public link.
An AI coding agent is only as useful as the context it can read. Give it too little and it makes confident guesses. Give it an entire workspace and you expose unrelated notes, credentials, client details, or half-finished decisions it never needed. The useful middle is scoped context: one task-shaped bundle, available long enough for the agent to fetch it and no longer.
This guide explains what to include, what to remove, and how Promptsson’s temporary Markdown snapshots provide a short-lived handoff without turning your private prompt library into a public document store.
Start with the job, not the archive
Do not begin by asking, “Which folder can I share?” Begin with, “What must the agent know to finish this task?” A good context bundle usually has five parts:
- Outcome. The concrete result you expect: fix a failing checkout test, review an API change, or turn a diagram into Terraform.
- Current state. The relevant implementation, decision, board card, or architecture nodes as they exist now.
- Constraints. Languages, frameworks, compatibility requirements, security rules, and decisions that must not change.
- Acceptance checks. The command or observable result that proves the work is done.
- Unknowns. Questions the agent should answer rather than quietly inventing an answer for.
That bundle is normally much smaller than a project wiki. Smaller context is not only safer; it is easier for the agent to weight correctly. An old note about a rejected design can no longer compete with the current task.
Remove secrets and unrelated private data
A temporary link reduces how long content is available. It does not make a secret safe to share. Before creating any agent handoff, remove:
- API keys, access tokens, session cookies, private keys, and connection strings.
- Customer names, personal data, private support messages, and production records.
- Internal URLs or identifiers the agent does not need.
- Instructions from copied web pages, issue comments, or documents that could act as untrusted prompt injection.
Replace a required secret with a name such as DATABASE_URL and describe what the value is
used for. If the agent needs to know the shape of a record, provide a small synthetic example
instead of a real customer row.
The same rule applies to diagrams. Select the services and connections that explain the change; leave unrelated environments, account numbers, and internal notes out of the snapshot.
Use a task-shaped Markdown handoff
Plain Markdown is a good interchange format for coding agents because it is readable by a person, easy to fetch with standard tools, and preserves headings, lists, code fences, and links without a proprietary client.
A useful handoff can be as short as this:
# Fix duplicate invoice emails
## Outcome
Send one receipt only after a successful charge.
## Relevant context
- Runtime: Node 22, TypeScript, PostgreSQL
- The request can be retried by the queue.
- `charge_id` is unique in the payments table.
## Acceptance
- Existing payment is not charged again.
- Receipt is sent once.
- `npm test -- invoice` passes.
## Open question
Should failed email delivery retry independently from payment?Notice what is missing: the rest of the roadmap, unrelated prompts, every database table, and a long persona telling the agent to be an expert. The context is specific enough to work from and small enough to audit before sharing.
If you need a reusable structure for the instruction itself, start with the code review checklist prompt or learn how to write a prompt you will actually reuse.
How Promptsson temporary snapshots work
Promptsson can create a temporary snapshot from one finished prompt, one board card, a whole board, a diagram, or selected diagram nodes. The browser sends only that selected scope to the snapshot endpoint. Promptsson returns a hard-to-guess URL whose response is plain, read-only Markdown.
The lifecycle is deliberately short:
- You choose the exact item or selection and create the snapshot.
- The snapshot is held in server memory, not added to a permanent prompt library.
- The agent fetches the URL once with its normal web-fetch tool or
curl. - After the first successful read, the snapshot is deleted.
- If nobody reads it, it expires after about two minutes.
A second fetch returns 404. You can also revoke an unread snapshot immediately from the
browser that created it. This makes the URL suitable for a live handoff, not documentation,
bookmarking, or collaboration history.
For example, an agent that can run a shell command can read the handoff with:
curl -sS https://promptsson.com/s/your-temporary-tokenCreate the snapshot immediately before the agent needs it. Do not paste the URL into a long-lived issue, chat room, commit message, or log. A short expiry limits accidental exposure; it does not undo copies made by the recipient after the first read.
Choose the smallest useful snapshot
Promptsson offers several snapshot scopes because different tasks need different context:
- Prompt: use for a finished instruction plus its resolved variables.
- Card: use for one task, its checklist, notes, and linked prompt.
- Board: use when status and neighboring work affect the decision.
- Diagram selection: use when the agent needs one subsystem rather than the entire architecture.
- Whole diagram: reserve for work where every service and connection is genuinely relevant.
Default downward. Start with a card instead of a board, or selected nodes instead of the whole diagram. If the agent identifies a missing dependency, create a fresh snapshot with that extra context. It is safer and usually faster than front-loading everything.
Verify the handoff before you send it
Take one minute to read the generated Markdown as if you were the agent:
- Is the requested outcome stated in the first screenful?
- Are names and acronyms explained?
- Does every included note affect the task?
- Are the acceptance checks runnable or observable?
- Did any secret, personal data, or untrusted instruction slip in?
- Is a rejected approach clearly marked as rejected?
Then give the agent one direct instruction: fetch the URL now, summarize the constraints it found, and ask about contradictions before editing. That confirmation catches expired links, missing context, and misunderstood requirements before the agent changes code.
When not to use a temporary snapshot
Use a normal version-controlled document when context must remain available for future maintainers, reviewers, or CI. Use your team’s authenticated file-sharing system when several people need ongoing access. Use a secret manager for credentials. A read-once link is intentionally the wrong tool for durable documentation, team collaboration, or secret distribution.
The useful pattern is simple: keep the full workspace private, select the smallest context that explains one job, remove anything sensitive, and make the handoff disappear after it is read. Open Promptsson to create a scoped snapshot, or read why the rest of the prompt library stays local.