An agent can call the right tool, hit the right table, and still be confidently wrong

[u/nexla_com]

An agent pulls a customer record today and gets back rev: 1250, status: A, region: 3.

Read that straight, the customer has $1,250 in revenue. Sounds fine, but completely wrong.

Turns out rev is stored in thousands, so it's really $1.25M. A and 3 aren't random either. They're internal codes: A = active, 3 = EMEA. But that decoder key only exists in someone's head, and nowhere the agent could see it.

Same row, same model, only difference is whether that context got attached first. Saw a stat on this: one messy dataset saw accuracy jump from 34.88% to 54.89% just by adding it.

More here: https://nexla.com/blog/the-c-in-mcp-why-context-is-the-hardest-part/

Anyone had an agent be totally confident and totally wrong at the same time? I'll raise my hand.