The Problem: HR Knowledge Queries in a 2,000-Employee B2B SaaS Firm
You run a 2,000-employee B2B SaaS company in Switzerland. Your HR and recruiting team handles 300 to 500 internal knowledge queries per week: onboarding steps, benefits eligibility, policy interpretations, and recruiting process questions. Each query takes a recruiter 12 to 18 minutes to answer manually, and the error rate on policy citations sits at 8 to 12 percent because staff pull from outdated PDFs. The EU AI Act, which applies to your operations because you serve EU customers, classifies HR and recruiting AI tools as high-risk under Annex III, point 4. You need to reduce the back-office error rate, cut cycle time, and ship a conversational agent inside Slack or Microsoft Teams that retrieves answers from your own documentation using pgvector embeddings. The rollout must be compliance-safe, human-in-the-loop, and delivered in 8 weeks with a measured before/after baseline.
Prerequisites: What You Need Before Week 1
Before you start the 8-week timeline, confirm the following are in place:
- Access to your HR knowledge base: a consolidated set of policy documents, job descriptions, onboarding guides, and recruiting SOPs in a format you can chunk and embed. If your documents live in SharePoint, Confluence, or a shared drive, export them to a staging folder.
- A PostgreSQL instance with the pgvector extension installed: you need a dedicated database or a schema within your existing PostgreSQL cluster. The instance must be on your own infrastructure or in a Swiss or EU data center to keep regulated HR data inside your jurisdiction.
- Slack or Microsoft Teams API credentials: you will build the conversational agent as a bot that responds in a dedicated HR channel. Request bot token permissions for
chat:write,reactions:write, andusers:readin Slack, or the equivalentChannelMessage.SendandUser.Readscopes in Teams. - A named human approver: the EU AI Act requires human oversight for high-risk systems. Identify one HR operations lead who will review and approve agent responses that touch compensation, contract terms, or personal data.
- A baseline measurement plan: before the pilot, log the cycle time and error rate for 50 representative HR queries over two weeks. This becomes your before/after benchmark.
Step 1: Run the AI Process Audit and Pick the Pilot Workflow
Run a process audit across your HR and recruiting workflows. Map every recurring knowledge query: onboarding, benefits, leave policy, recruiting process, contract templates. For each workflow, record the current cycle time, the number of manual steps, and the error rate. Use a simple spreadsheet with columns for workflow name, query volume per week, average handling time, and error count. This audit identifies which workflows are worth automating. For a 2,000-employee firm, you will typically find that onboarding and benefits queries account for 60 to 70 percent of volume. Select one workflow for the pilot: onboarding knowledge search is the most common choice because it has high volume, low regulatory sensitivity, and a clear success metric.
Step 2: Build the pgvector Embedding Pipeline
Chunk your HR policy documents into passages of 200 to 400 tokens each, preserving section headers as metadata. Use a sentence-aware chunker so you do not split a policy clause across two chunks. Embed each chunk using a model that supports multilingual output if your HR team works in German, French, or Italian alongside English. Store the embeddings in a pgvector table with an HNSW index. The configuration looks like this:
CREATE EXTENSION IF NOT EXISTS vector;
CREATE TABLE hr_documents (
id SERIAL PRIMARY KEY,
content TEXT NOT NULL,
metadata JSONB,
embedding vector(1536)
);
CREATE INDEX ON hr_documents USING hnsw (embedding vector_cosine_ops);
The HNSW index with vector_cosine_ops gives you sub-50 ms retrieval on a dataset of up to 50,000 chunks. Test the index by running a query for a known question and confirming the top-3 results match the expected document sections.
Step 3: Build the Conversational Agent with Human-in-the-Loop Approval
Build the conversational agent as a Slack or Teams bot. The agent receives a user query, sends it to the pgvector database for retrieval, and passes the top-3 retrieved passages to a language model for response drafting. Use a model-agnostic approach: call OpenAI or Anthropic APIs for general policy questions, and route sensitive queries to an open-weight model running on your own hardware if the data cannot leave your infrastructure. The agent must include a confidence score from the retrieval step. If the cosine similarity of the top result is below 0.75, the agent flags the response for human review. The bot posts the draft response in the HR channel with a @hr-approver mention. The approver clicks an Approve or Reject button. Only after approval does the response become visible to the querying employee. Log every query, retrieval result, and approval decision to a PostgreSQL table for EU AI Act Article 12 compliance.
Step 4: Run the Pilot and Measure the Before/After Baseline
Run the pilot with a group of 10 to 15 HR staff for two weeks. Measure three metrics daily: cycle time per query, error rate on policy citations, and user satisfaction score on a 1 to 5 scale. Compare these against the baseline you captured in the prerequisites. The target for the pilot is a 40 to 60 percent reduction in cycle time and a drop in error rate from 8 to 12 percent down to below 3 percent. If the error rate does not improve, check the retrieval quality: run the golden set of 50 known questions through the pgvector index and verify that the top-3 passages match the expected documents. If retrieval is accurate but the error rate is still high, the problem is in the language model’s response drafting. Adjust the prompt to include the retrieved passages verbatim and instruct the model to cite the source document section. Document every configuration change in your technical file under EU AI Act Article 11.
Step 5: Roll Out to the Full HR Team and Hand Over Managed Operations
Roll out the agent to the full HR and recruiting team. Migrate the bot from the pilot channel to the main HR channel in Slack or Teams. Update the onboarding documentation so new HR hires know how to query the agent and when to escalate to a human. Set up a weekly operations cadence: the managed AI operations team reviews the query log, checks for embedding drift by re-running the golden set, and re-embeds any documents that have been updated. The re-embedding job runs every Monday at 02:00 UTC. Monitor the error rate and cycle time weekly. If the error rate rises above 5 percent for two consecutive weeks, trigger a root-cause analysis. The managed operations team also handles incident response: if the agent returns an incorrect policy citation that reaches an employee, the approver logs the incident, the team corrects the document, re-embeds it, and documents the fix in the technical file. This keeps the system compliant under EU AI Act Article 14 human oversight requirements.
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