AI
GenAI
The Responsibilities MCP Separates, Part 2 — Separating Identity from Permission to Data
MCP v2026-07-28 uses Bearer access tokens to establish the requester at the router and to decide whether that requester may operate on business data.
Posts tagged#Distributed Systems
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AI
GenAI
The Responsibilities MCP Separates, Part 1 — Moving Protocol State Out of the Session
MCP v2026-07-28 separates protocol state from application state that once shared a connection, allowing any instance to process a request. A visual guide to the fields and flow.
ALOPEX
Alopex DB
What Is the Best Database for a Startup? — A Stage-by-Stage Use-Case Analysis and the 'Scaling Cliff'
An analysis of how database requirements change across the MVP, PMF, growth, and scale stages, comparing the trade-offs of SQLite, Postgres, managed databases, and dedicated vector stores — and where Alopex DB's 'erase the migration cliff' approach fits.
DATA
Data & DB
What Alopex Chirps Is — A Library for Forming Clusters, and the Consensus It Adopted
Building a distributed system means building node discovery, liveness detection, messaging, and agreement before getting to the actual work. Alopex Chirps takes on exactly those four. This covers what it handles and what it does not, why QUIC was chosen, and how openraft came to be the consensus layer.
DATA
Data & DB
Consensus Algorithms, Underground (Part 4) — A World Where Identities Cannot Be Counted: PoW and PoS
In a network where neither the identity nor the number of participants is known, one node one vote does not hold. Probabilistic finality in PoW, the structure by which PoS relies on economic penalties rather than impossibility, Solana and Avalanche, and the option of avoiding agreement — with the criteria for choosing among them. Part 4 of a 4-part series.
DATA
Data & DB
Consensus Algorithms, Underground (Part 3) — Lying Nodes, from PBFT to DAG-BFT
The world in which nodes send signed, contradictory information. The meaning of the constant n=3f+1, PBFT's three-phase voting, Tendermint's locking rules, HotStuff's quorum certificates, and what the DAG-BFT designs since Narwhal separated and what they removed. Part 3 of a 4-part series.
DATA
Data & DB
Consensus Algorithms, Underground (Part 2) — The Crash Failure Family: Paxos and Raft
The family of algorithms for the crash failure model, where nodes stop but do not lie. From the single tool Paxos relies on — quorum intersection — through Raft's decomposition, EPaxos, Multi-Raft, and the parts outside the papers: persistence ordering and linearizable reads, with minimal code. Part 2 of a 4-part series.
DATA
Data & DB
Consensus Algorithms, Underground (Part 1) — Crashes and Delays Are Indistinguishable
A node that stops responding may have crashed, or it may merely be slow; the two cannot be told apart. This part separates leader election, ordering, and commitment into three distinct problems, and covers the practical meaning of FLP impossibility, split brain and fencing tokens, and the boundary between the replicated log and the applied state. Part 1 of a 4-part series.
AIAIALOPEXDATADATADATADATADATA
The Responsibilities MCP Separates, Part 2 — Separating Identity from Permission to Data
MCP v2026-07-28 uses Bearer access tokens to establish the requester at the router and to decide whether that requester may operate on business data.
The Responsibilities MCP Separates, Part 1 — Moving Protocol State Out of the Session
MCP v2026-07-28 separates protocol state from application state that once shared a connection, allowing any instance to process a request. A visual guide to the fields and flow.
What Is the Best Database for a Startup? — A Stage-by-Stage Use-Case Analysis and the 'Scaling Cliff'
An analysis of how database requirements change across the MVP, PMF, growth, and scale stages, comparing the trade-offs of SQLite, Postgres, managed databases, and dedicated vector stores — and where Alopex DB's 'erase the migration cliff' approach fits.
What Alopex Chirps Is — A Library for Forming Clusters, and the Consensus It Adopted
Building a distributed system means building node discovery, liveness detection, messaging, and agreement before getting to the actual work. Alopex Chirps takes on exactly those four. This covers what it handles and what it does not, why QUIC was chosen, and how openraft came to be the consensus layer.
Consensus Algorithms, Underground (Part 4) — A World Where Identities Cannot Be Counted: PoW and PoS
In a network where neither the identity nor the number of participants is known, one node one vote does not hold. Probabilistic finality in PoW, the structure by which PoS relies on economic penalties rather than impossibility, Solana and Avalanche, and the option of avoiding agreement — with the criteria for choosing among them. Part 4 of a 4-part series.
Consensus Algorithms, Underground (Part 3) — Lying Nodes, from PBFT to DAG-BFT
The world in which nodes send signed, contradictory information. The meaning of the constant n=3f+1, PBFT's three-phase voting, Tendermint's locking rules, HotStuff's quorum certificates, and what the DAG-BFT designs since Narwhal separated and what they removed. Part 3 of a 4-part series.
Consensus Algorithms, Underground (Part 2) — The Crash Failure Family: Paxos and Raft
The family of algorithms for the crash failure model, where nodes stop but do not lie. From the single tool Paxos relies on — quorum intersection — through Raft's decomposition, EPaxos, Multi-Raft, and the parts outside the papers: persistence ordering and linearizable reads, with minimal code. Part 2 of a 4-part series.
Consensus Algorithms, Underground (Part 1) — Crashes and Delays Are Indistinguishable
A node that stops responding may have crashed, or it may merely be slow; the two cannot be told apart. This part separates leader election, ordering, and commitment into three distinct problems, and covers the practical meaning of FLP impossibility, split brain and fencing tokens, and the boundary between the replicated log and the applied state. Part 1 of a 4-part series.