Architecture overview / simplified for the case study. Stage widths do not encode timings.
More than one answer
I built the agent layer for questions that needed several answers from different tools. The existing guardrails got in the way of complex, multi-part queries. Retrieving tools for the whole message could miss a secondary part of the question, so the work centered on covering each part and coordinating the calls needed to answer it.
Tools and tenant scope
Embedding-based retrieval selected relevant tools from the wider catalog. My backend work also moved database access onto organization-scoped sessions enforced by PostgreSQL row-level security, then addressed the query plans behind a slow handler.
What the baseline says
The reviewed baseline has 75 passing prompts out of 229, or 32.8%. My resume reports an end-to-end accuracy improvement from 33% to 99%. That is a separate reported result, not a demonstrated follow-up evaluation of those same 229 prompts.
What the evidence says.
reported
Agent end-to-end accuracy
hemut-mcp
33% / to99%
Original resume outcome for the MCP agent layer and embedding-based tool retrieval. The reviewed baseline is recorded separately; no paired after-evaluation artifact is supplied for the 99% figure.
Source
Original resume: Hemut copilot accuracy
measured
Reviewed prompt baseline
hemut-mcp
32.8%
75 passing prompts divided by 229 reviewed prompts, rounded to one decimal place. This supports the baseline only, not a subsequent accuracy result.
Source
Internal prompt evaluation: reviewed June 16 run
Sample
75 passing / 229 reviewed prompts
Recorded
2026-06-16
reported
MCP tool catalog
hemut-mcp
192 tools
Tool catalog size reported in the original resume, with embedding-based retrieval selecting relevant tools. This is an implementation-scale figure, not an accuracy measurement or a current registry audit.
Source
Original resume: Hemut MCP tool catalog
reported
Worst database handler
hemut-mcp
10.2 s / to487 ms
Original resume reports organization-scoped, row-level-security-enforced sessions across a nine-organization Postgres estate, followed by query-plan fixes. The reported handler timings have no specified percentile or load.
Source
Original resume: Hemut database hardening
Credits
Agent and backend engineering by DongYeop Lee at Hemut.