base64_encodeEncode UTF-8 text to Base64 / Base64URL / Base32 / Hex (keyless, offline). Set variant (default base64).
| Name | Required | Description | Default |
|---|---|---|---|
| text | Yes | Text to encode. | |
| variant | No | Encoding: base64 (default), base64url, base32, or hex. |
Changes observed during successful MCP inspections.
Input schema / examplesAdded value: +[
+ {
+ "text": "Hello, World!"
+ },
+ {
+ "text": "Sensitive information",
+ "variant": "base64url"
+ }
+]Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations indicate read-only, idempotent, and non-destructive behavior. The description adds that the encoding is keyless and offline, providing extra behavioral context. No contradictions with annotations.
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 extremely concise: two sentences that clearly state the purpose and mention the parameter. It is front-loaded with the core functionality and contains no unnecessary words.
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 encoding tool with no output schema, the description provides sufficient context: input type (UTF-8 text), available encoding options, and key properties (offline, keyless). It is complete enough for an agent to understand the tool's capabilities.
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 the schema already documents both parameters. The description mentions the default for 'variant' (base64), adding a small amount of value beyond the schema. 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 clearly states the tool's purpose: encoding UTF-8 text to Base64, Base64URL, Base32, or Hex. It specifies that the operation is keyless and offline, and the sibling tool base64_decode provides the inverse, making the purpose distinct.
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 does not provide explicit guidance on when to use this tool versus alternatives (e.g., base64_decode). However, the purpose is clear from the description, and the agent can infer usage from the naming and context. No exclusion criteria or suggested contexts are mentioned.
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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