Bitcoin Developers Debate PR to Filter Inscriptions – Key Arguments For and Against

In September 2023, Bitcoin developer Luke Dashjr submitted a pull request (PR) to the Bitcoin Core GitHub repository proposing changes to the datacarriersize parameter. The goal? To allow node operators to filter out transactions embedding large amounts of data—particularly those associated with Bitcoin inscriptions, such as Ordinals and NFTs—by extending existing data limits beyond just OP_RETURN outputs to include witness data.

While the PR sparked intense debate among core developers, it was ultimately closed in January 2024 by Bitcoin Core maintainer achow101, who noted that the proposal was highly controversial and unlikely to gain consensus in its current form. Another maintainer, gloria, later summarized the key arguments from both supporters and opponents of the change.

This article breaks down the core perspectives, technical implications, and philosophical divides behind this pivotal moment in Bitcoin’s evolution—highlighting why the debate over inscriptions, network usage, and node policy remains far from settled.

What the PR Proposed: Extending datacarriersize to Witness Data

By default, Bitcoin Core limits the amount of data that can be embedded in OP_RETURN outputs to 80 bytes. Users can adjust this via the -datacarriersize configuration option. However, this limit previously applied only to OP_RETURN, not to other methods of data embedding—such as witness scripts used by Ordinals inscriptions.

Luke Dashjr’s PR aimed to extend this same restriction to witness data, specifically targeting common inscription patterns like the OP_FALSE OP_IF ... OP_ENDIF structure. It did not attempt to universally detect all forms of embedded data—since no foolproof method exists—but focused on known exploitation vectors.

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Core Keywords

• Bitcoin inscriptions
• Ordinals protocol
• Node policy
• Data carrier size
• Mempool filtering
• Bitcoin scalability
• Decentralized network

These keywords reflect the central themes of technical governance, network health, and user sovereignty in Bitcoin’s ongoing development.

Arguments in Favor of Filtering Inscriptions

1. "Inscriptions Are Spam—They Harm Bitcoin’s Primary Function"

Many developers argue that inscriptions represent spam transactions that degrade Bitcoin’s utility as a peer-to-peer electronic cash system.

• Inscriptions, NFTs, and arbitrary data storage use cases generate high-volume, non-financial traffic.
• This leads to network congestion, higher fees, and slower confirmation times for legitimate payments.
• Some label this behavior a form of DDoS attack, where economic incentives push out everyday users.
• Since Bitcoin’s whitepaper emphasizes financial transactions, storing large metadata is seen as a misuse of the protocol.

Supporters believe that allowing unchecked data bloat undermines Bitcoin's original vision: a decentralized, low-cost payment network.

2. "Embedded Data Increases Node Operating Costs"

Running a full node should be accessible. But inscription-heavy blocks increase:

• Disk storage requirements
• Bandwidth consumption
• Validation complexity

This disproportionately impacts independent node runners, potentially leading to centralization, as only well-resourced entities can afford to stay online.

“If node operation becomes too expensive, decentralization erodes.” — Developer comment on GitHub

The PR was seen as a tool to help protect node operators from bearing the cost of others’ data experiments.

3. "Users Should Have Built-In Control Over Mempool Policy"

Node operators want autonomy. Without built-in filtering tools, they may resort to:

• Manually patching their nodes
• Using unstable third-party software
• Risking security or compatibility issues

By extending -datacarriersize, users could opt-in to filter unwanted data—just as they already do with OP_RETURN. This isn’t censorship; it’s user empowerment.

Miners who prioritize Bitcoin as digital money rather than an immutable ledger might also prefer filtering spam to keep transaction fees reasonable and throughput efficient.

4. "This Is Just Fixing a Bug in datacarriersize"

Proponents argue this change isn’t a new policy—it’s a bug fix.

• The intent of -datacarriersize has always been to limit arbitrary data in transactions.
• SegWit and Taproot introduced new ways to embed data outside OP_RETURN, but the setting wasn’t updated accordingly.
• Now, inscriptions exploit this gap by storing data in witness fields—effectively bypassing existing limits.

Thus, updating the rule ensures consistency across all data-carrying methods, closing what some see as an unintended loophole.

Arguments Against Filtering Inscriptions

1. "It Won’t Stop Inscriptions—Miners Have Incentives to Include Them"

Even if some nodes filter inscription transactions, miners can still include them—and they’re financially motivated to do so.

• Inscription transactions often pay very high fees, sometimes tens of BTC per block.
• A miner filtering these transactions would earn less than competitors who accept them.
• This creates a direct economic disincentive for adoption.

Moreover:

• Transactions can bypass public mempools entirely via private channels.
• Blocks built from filtered mempools yield lower rewards → less competitive mining.

“Filtering reduces your income. The market will favor those who don’t.”

Eventually, this could push transaction flow into private relay networks, increasing mining centralization risks.

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2. "You Can’t Technically Block All Data Embedding Methods"

There is no universal way to detect every method of embedding arbitrary data in Bitcoin transactions.

• New techniques will always emerge.
• Trying to patch each one leads to an endless cat-and-mouse game in critical consensus code.
• Complex detection logic increases attack surface and maintenance burden.

Instead, critics argue for focusing on efficiency: let markets decide which data-carrying methods survive based on resource cost and utility.

Trying to ban all non-financial uses through code risks making Bitcoin rigid and harder to maintain.

3. "Changing Default Policies Can Harm Network Integrity"

Altering default mempool behavior affects more than just spam filtering.

• Nodes running the filter may fail to relay valid transactions soon to be mined.
• This breaks their ability to accurately predict upcoming blocks.
• It harms fee estimation models and slows down block validation.
• In extreme cases, users might struggle to spend funds if their transactions are deemed "non-standard."

Critics warn that changing defaults without opt-in mechanisms risks:

• Fragmentation
• Reduced interoperability
• A form of soft confiscation, where access to funds becomes harder due to policy shifts

Bitcoin’s strength lies in predictability. Arbitrary policy changes undermine trust in the system’s neutrality.

4. Additional Concerns Raised by Opponents

• Mempool policy is no longer effective at controlling usage: With full blocks now routine, filtering doesn’t reduce long-term node costs—it only delays propagation.
• Market demand determines use cases: If users pay high fees for inscriptions, that reflects real demand. Developers shouldn’t impose top-down restrictions on how people use their coins.
• Bitcoin is permissionless and decentralized: No single group should dictate acceptable use. Whether you like inscriptions or not, the network allows them—and that’s by design.
• The PR alters -datacarriersize semantics: It bundles two distinct policies—OP_RETURN limits and witness data filtering—making it impossible to replicate pre-change defaults even if desired.

Frequently Asked Questions (FAQ)

Q: Does this PR ban inscriptions outright?

A: No. It only allows node operators who configure -datacarriersize to filter certain types of data-heavy witness scripts. It does not prevent miners from including inscriptions in blocks.

Q: Can inscriptions be completely stopped technically?

A: Not realistically. There are multiple ways to embed data in Bitcoin transactions, and new methods may emerge. Any filtering solution will be partial and potentially circumventable.

Q: Why did Bitcoin Core maintainers close the PR?

A: Due to lack of consensus. The change was controversial, with strong arguments on both sides. Maintainers concluded it wouldn’t reach broad agreement and risked destabilizing core node behavior.

Q: Are inscriptions harmful to Bitcoin?

A: Opinions differ. Some say they increase fees and strain nodes; others argue they bring innovation, usage diversity, and economic activity. The impact depends on one’s view of Bitcoin’s purpose.

Q: Could this lead to a fork?

A: Unlikely in this case. Since the PR was rejected and no major mining pool or client has adopted it, there’s no immediate threat of chain split. But future policy conflicts could reignite such debates.

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Conclusion: A Philosophical Crossroads for Bitcoin

The debate over filtering inscriptions isn't just technical—it's deeply philosophical.

On one side: those who see Bitcoin as electronic cash, optimized for fast, cheap payments and sustainable node operation.

On the other: those who embrace Bitcoin as a censorship-resistant, permissionless ledger, where innovation—even controversial forms like NFTs—should emerge organically.

Luke Dashjr’s PR highlighted a growing tension: who decides what belongs on Bitcoin? Developers? Miners? Users?

For now, the answer remains decentralized: no single group controls the rules. But as new use cases challenge old assumptions, these debates will only intensify.

What’s clear is that user choice, economic incentives, and technical pragmatism must all be balanced carefully—without compromising Bitcoin’s core principles of openness and resilience.