Errors - LePosta

Tool errors come back as a normal tool result with isError: true and a single text message. Messages are written for the model: each one says what to change. LePosta never returns stack traces or internal details.

{ "isError": true, "content": [{ "type": "text", "text": "Posta 01M5F4D1NEATEFTXG8ZVFN8KKY not found." }] }

Input

Message	Cause
`Invalid input. title must be at most 80 characters; shorten it.`	A field is over its limit. Each field has its own message.
`Invalid input. <field> has the wrong type (expected string).`	Wrong JSON type for a field.
`Input validation error: Invalid arguments for tool <name>: ...`	A required argument is missing or an enum value is unknown. This one comes from the MCP SDK, before LePosta’s own checks.
`surface.at must be an ISO 8601 date with a UTC offset in the user's local time, for example 2026-10-21T09:00:00-03:00.`	A date without an offset or not in ISO 8601. `snooze_until` gives the same message.
`surface.at must be in the future.` / `must be at most 180 days from now.`	Scheduled or snooze date out of range.
`surface.at is required when surface.mode is "at".`	`mode: "at"` without a date.
`surface.at is only used when surface.mode is "at".`	A date with another mode.
`surface.mode "project_open" requires project.`	`project_open` without `project`.
`Provide status, snooze_until, or both.`	`update_status` with neither.
`<field> looks like it contains a GitHub token. Remove it and try again: postas must never include passwords, API keys, tokens or customer data.`	Secret detection. Nothing is saved.

Access and visibility

Message	Cause
`Posta <id> not found.`	The posta doesn’t exist or belongs to someone else. Both answer the same.
`You can only set the status of postas addressed to you.`	Changing the status of a handoff you sent, or `reply` with `status` on a posta not addressed to you.
`This GitHub account no longer has access to LePosta. Tell the user to ask whoever invited them.`	The account was removed from the allowlist.

Handoffs and replies

Message	Cause
`You can't send a handoff to yourself: use create_note for notes to yourself.`	`to` is your own username.
`@x is not in your LePosta group. Use whoami to see who you can send handoffs to.`	The recipient isn’t on the allowlist.
`@x has not signed in to LePosta yet; ask them to connect once.`	The recipient is invited but never signed in.
`You can't reply to your own note. Use update_status to change it, or create_note for a new note.`	`reply` on a note.
`This thread reached its limit of 3 replies. If you need to continue, send a new handoff with send_handoff.`	Thread depth limit.

Limits

Message	Cause
`You have created 60 postas in the last hour, the hourly limit. Wait a while before creating more.`	Hourly creation limit.
`Your inbox has 100 pending postas, the limit. Mark some as done or dismissed with update_status before saving more.`	Your inbox is full (notes).
`@x's inbox is full (100 pending postas). Ask them to clear some first.`	The recipient’s inbox is full (handoffs and replies).

When a write is refused, nothing is saved: no posta, no reply, no status change.

Server

Message	Cause
`LePosta had an internal error. Try again in a moment; if it keeps failing, tell the user.`	An unexpected failure. Details are only in the server logs.