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

With no annotations provided, the description carries the full behavioral burden, and it discloses nothing: not what happens when the separator is absent, nor whether matching is case-sensitive, first-occurrence, or last-occurrence, nor what the output looks like.

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?

It is short, but brevity here comes from under-specification rather than efficiency: the single clause is a verbatim duplication of the name with no informational content.

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 three-parameter string-manipulation tool with no annotations and no output schema, this description supplies none of the operational detail an agent needs 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 description coverage is 100%, so all three parameters (text, input, separator) are documented in the schema, which sets the baseline at 3. The description adds nothing to disambiguate the redundant text/input fields, but the schema does the heavy lifting.

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?

"Substring After: Substring After" merely repeats the tool name and title. It does not state in plain terms that it returns the portion of a string following a separator, nor does it distinguish itself from the sibling tools x402-substring-before and x402-substring-between.

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?

There is no guidance about when to use this tool versus x402-substring-before, x402-substring-between, x402-split-complementary, or generic extract helpers. No prerequisites, edge cases, or alternatives are mentioned.

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