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superposition_view

Superpose two protein structures and color the mobile one by per-residue shift, from blue (unchanged) to red (most moved), to visualize which regions differ.

Instructions

Superposes two structures and colors the mobile one by per-residue shift.

An RMSD alone tells you that something moved, not where. This superposes mobile onto target, measures how far each residue's CA ended up from its counterpart, and colors the mobile structure blue (unchanged) through white to red (most shifted). The target is left as a grey reference cartoon.

Best on two states of the same protein — apo vs holo, open vs closed, a mutant against wild type. Residues are paired by chain and residue number, falling back to residue number alone when the two use different chain IDs.

Both structures have to be loaded first, and fetch_structure clears the session by default — so fetch the second one with replace=False or it will replace the first. If either entry is a multimer, compare single chains (create one object per chain): superposing one dimer onto another fits the assembly rather than the fold, which inflates the RMSD dramatically. 4AKE against 1AKE gives 18.5 A as deposited dimers and 2.1 A chain-to-chain.

Input Schema

TableJSON Schema
NameRequiredDescriptionDefault
methodNo"super" (default) is sequence-independent and handles low identity or different folds; "align" uses a sequence alignment first and is better for near-identical sequences.super
mobileYesObject to move and color (e.g. "1ake").
targetYesObject to superpose onto and leave in place (e.g. "4ake").
max_deviationNoAngstrom value mapped to full red. Defaults to the largest observed shift, which maximises contrast; set it explicitly to compare two different pairs on one scale.

Output Schema

TableJSON Schema
NameRequiredDescriptionDefault
resultYes
Behavior5/5

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

With no annotations, the description carries full responsibility, and it delivers thoroughly. It discloses the coloring gradient (blue-white-red), that the target is left grey, residue pairing logic by chain and number with fallback, and the multimer pitfall with a specific numeric illustration (4AKE vs 1AKE). It also explains the meaning of max_deviation in the workflow. No annotation contradiction exists.

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

Conciseness5/5

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

The description is appropriately sized for its complexity. Each sentence adds necessary information: the core purpose, the rationale versus RMSD, the coloring mechanism, usage scenarios, pairing rules, and crucial caveats. It is well-structured, starting with a clear statement and then expanding into practical details without redundancy.

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

Completeness5/5

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

The tool is complex with visual output and multiple parameters, but the description covers all essential aspects: the operation, coloring logic, pairing behavior, prerequisites, and edge cases. It even gives a concrete example to illustrate the multimer issue. An output schema exists, so return-value documentation is not required. The description is complete enough for an agent to use the tool correctly and safely.

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

Parameters4/5

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

Schema coverage is 100%, so the baseline is 3. The description adds value beyond the schema by explaining the max_deviation behavior (defaults to largest observed shift, set explicitly to compare pairs) and implying how mobile/target relate via the superposition concept. However, it does not fully elaborate on method choices; still, the schema already provides clear field descriptions, so the added semantic context is a bonus.

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 opens with a specific verb-resource combination: 'Superposes two structures and colors the mobile one by per-residue shift.' It clearly distinguishes this from sibling tools by explaining that it provides per-residue visualization rather than just an RMSD number, and the explicit mention of 'mobile onto target' and coloring scheme establishes a unique identity.

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

Usage Guidelines5/5

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

The description explicitly states when the tool is best used: 'Best on two states of the same protein — apo vs holo, open vs closed, a mutant against wild type.' It also provides critical practical guidance: both structures must be loaded, warns about fetch_structure clearing the session, recommends replace=False, and cautions against multimers with a concrete example. This goes beyond simple context to include exclusions and workarounds.

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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