Apply the Atbash substitution (A to Z, Z to A) to encode or decode text. Pure CPU, instant.
Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.
{
"id": 1,
"jsonrpc": "2.0",
"method": "tools/call",
"params": {
"arguments": {
"text": "<text>"
},
"name": "atbash"
}
}| Name | Required | Description | Default |
|---|---|---|---|
| text | Yes | Text to transform |
Changes observed during successful MCP inspections.
Input schema / properties / textAdded value: +{
+ "description": "Text to transform",
+ "type": "string"
+}Input schema / requiredAdded value: +[
+ "text"
+]Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations supplied, the description carries the full burden, and it does disclose that the operation is pure CPU and instant, implying a safe, side-effect-free transform. It omits what happens to non-alphabetic characters (digits, punctuation, non-ASCII) and does not state that output is the same length as input, which matters for a text transform.
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?
Two short sentences, front-loaded with the operation and its mapping, with zero wasted wording. The 'Pure CPU, instant' note is terse and adds practical value.
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?
For a simple, deterministic, single-parameter transform with no output schema or annotations, the description covers the essentials: what it does, that it is reversible, and that it is cheap to run. Only the treatment of non-alphabetic input remains unstated, a minor gap for this complexity level.
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% and the single parameter is documented as 'Text to transform', so the schema does the heavy lifting. The description adds no further meaning about the parameter (e.g., whether case is preserved or non-letters pass through), so baseline 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 names the specific operation (Atbash substitution) and spells out the mapping (A to Z, Z to A), so an agent knows exactly what transformation occurs. It does not, however, distinguish itself from near-neighbors like caesar_cipher or rot13 in the sibling list, leaving that inference to the agent.
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?
It clarifies the key usage fact that the same call both encodes and decodes (Atbash is its own inverse), which is genuinely useful. It gives no explicit when-to-use versus other cipher tools such as caesar_cipher, rot13, or vigenere, so routing guidance is only implied.
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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