Library guide · 11 February 2026
Program logs after the slot is closed
Log lines are the program speaking after execution: invoke, success, or the instruction error that stopped the message.
Invoke, then a matching success or failure
A confirmed Solana transaction carries log messages in its meta. A typical program writes a line when it is invoked and another when it returns. The number in brackets is the depth. An outer program is invoke [1]. A program it calls is invoke [2]. We read these with a finger on the paper so the depth does not get flattened into a single “it failed.”
Inner instructions, listed separately in meta, are the calls that happened during execution. They are not a second transaction. They are the same transaction, seen from inside the first program. The library guide keeps the log lines and the inner-instruction list on facing pages.
Where the error points
If the transaction failed, meta.err names the instruction index and the error. Custom program errors are numbers the program chose. The log line just above the failure often has the program’s own text, which is more specific than the numeric code and still needs the instruction index so you know which call emitted it.
We do not treat a log line as a verdict on the whole account list. A token program can succeed inside a larger message that later fails. The depth and the index tell you which of those you are looking at.
What we will not infer
Logs say what the program printed and whether the runtime aborted an instruction. They do not, by themselves, say whether a person meant to send that transaction, whether a price was fair, or whether a later transaction repaired the damage. Those questions need the surrounding signatures, and sometimes a person who was there. The reading hour on this guide stops at the lines.
If you want those lines marked on your own signature, book the signature walkthrough and say that the logs are the part you care about. Hana will still read the header first, briefly, because a log without the instruction index is a loose strip of paper.
If this is the field you want marked on your own signature, reserve a signature walkthrough or book a reading hour and name the guide.