USE THIS to verify an ISBN-10 (older book identifier) instead of trusting 10 characters. Checks the mod-11 check digit (which may be 'X'). For 13-digit ISBNs use validate_isbn.
| Name | Required | Description | Default |
|---|---|---|---|
| isbn | Yes | The ISBN-10 (hyphens/spaces ignored). |
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?
Annotations provide readOnlyHint=true; description adds behavioral detail: 'checks the mod-11 check digit (which may be 'X')'. No contradiction.
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 sentences, no waste, front-loaded with actionable instruction.
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?
Simple tool with one parameter, readOnly annotation, no output schema. Description provides sufficient context for correct usage.
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 has 100% coverage for the single parameter with description. Description adds 'hyphens/spaces ignored', which is useful but not essential beyond schema.
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?
Description clearly states 'verify an ISBN-10' and 'checks the mod-11 check digit', with explicit differentiation from validate_isbn for 13-digit ISBNs.
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?
Explicitly states when to use this tool (for ISBN-10) and when not to (for 13-digit ISBNs use validate_isbn).
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Add one secure layer between your agents and this server.