evm_storageReads a raw storage slot of any contract, decoded as hex, integer and address. How you inspect proxy implementation slots, owners and paused flags that have no public getter. Flat $0.001 per call, paid over x402 (USDC).
| Name | Required | Description | Default |
|---|---|---|---|
| slot | No | Slot number in decimal, or a 0x slot key such as an EIP-1967 hash. | |
| chain | No | base | ethereum | polygon | arbitrum | optimism. | |
| address | Yes | Contract to read. |
Changes observed during successful MCP inspections. Dates show when Glama detected each change.
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description must carry behavioral disclosure. It reveals the output format (decoded as hex, integer, address) and the cost (flat $0.001 per call, paid via x402/USDC), which are useful. However, it does not mention potential errors, limits, or that it is a read-only operation beyond the verb 'reads', which is implicit.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
The description is concise: three sentences, each with a clear role. The first sentence states the action and output, the second gives use cases, and the third states pricing. It is front-loaded with the core purpose and contains no filler.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
The description explains the return values (hex, integer, address) and the cost, which is important since there is no output schema. However, it does not clarify default behavior when optional parameters (slot, chain) are omitted, or how the result is structured. This is a minor gap, but overall the tool is adequately described for an agent to call it correctly.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema coverage is 100%, so parameters are already documented. The description does not add extra meaning to the parameters themselves; it only mentions output decoding, which is not parameter-specific. According to the baseline for high coverage, a score of 3 is appropriate.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description clearly states the tool reads a raw storage slot from any contract, and it distinguishes itself from sibling EVM tools by specifying the exact resource (raw storage) and the purpose (inspecting proxy implementation slots, owners, paused flags without getters). It uses a specific verb and resource, and the use cases differentiate it from balance, call, and transaction tools.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description implies when to use it: when there is no public getter, such as for proxy implementation slots or paused flags. It gives concrete examples but does not explicitly name alternatives like evm_call for public getters. The guidance is clear but not exhaustive, missing an explicit 'when not to use'.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.