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pwndbg_largebins

Print the contents of an arena's large bins to inspect heap chunks sorted by size in doubly-linked lists, ideal for glibc ptmalloc2 heap analysis.

Instructions

Print the contents of an arena's large bins.

pwndbg command: largebins Source: pwndbg/commands/ptmalloc2.py Category: GLibc ptmalloc2 Heap

Large bins hold chunks >= 0x400 bytes (64-bit) in doubly-linked lists sorted by size within each bin.

Args: session_id: The UUID of the session. addr: Optional arena address. verbose: If True, show extended details.

See: https://pwndbg.re/2025.05.30/reference/pwndbg/commands/ptmalloc2/

Input Schema

TableJSON Schema
NameRequiredDescriptionDefault
session_idYes
addrNo
verboseNo

Output Schema

TableJSON Schema
NameRequiredDescriptionDefault
resultYes
Behavior2/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

No annotations are provided, so the description must fully convey behavioral traits. It states it prints large bins but does not disclose that it is a read-only operation, nor mention any prerequisites, side effects, or safety guarantees. This is insufficient for a tool with no annotation support.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is concise with front-loaded primary action. It includes source and category info that, while not essential, adds context. Each sentence contributes value, though the pwndbg command and source line could be omitted for brevity.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given no annotations, no output schema provided, and 0% schema coverage, the description is fairly complete: it states purpose, parameter meanings, and includes a reference link. It lacks details on output format, but an output schema exists (though not shown) to cover return values.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters5/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The description explicitly explains each parameter: session_id is 'The UUID of the session', addr is 'Optional arena address', verbose is 'If True, show extended details.' Since the schema has 0% description coverage, this adds critical meaning beyond the schema's minimal titles and types.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states 'Print the contents of an arena's large bins.' It specifies the resource (arena's large bins) and includes technical context (chunks >= 0x400 bytes, sorted by size). This distinguishes it from sibling tools like pwndbg_smallbins and pwndbg_fastbins.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines3/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description provides background on large bins but does not explicitly state when to use this tool over alternatives like pwndbg_bins or pwndbg_smallbins. It lacks guidance on when-not-to-use or explicit exclusions, so usage is implied but not clarified.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

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