isbn_checkValidate an ISBN-10 (mod-11) or ISBN-13 (1,3-weight mod-10) checksum.
| Name | Required | Description | Default |
|---|---|---|---|
| isbn | Yes | ISBN-10 or ISBN-13; dashes/spaces allowed. |
| Name | Required | Description | Default |
|---|---|---|---|
| tool | No | ||
| scope | No | ||
| valid | Yes | ||
| reason | Yes | ||
| country | No | ||
| normalized | No |
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint and idempotentHint, covering safety and repeatability. The description adds the behavioral specifics of supporting both ISBN-10 and ISBN-13 checksums and names the exact validation method, going beyond the structured fields. No annotation contradiction exists.
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?
A single sentence with zero filler; the subject, resource, and algorithmic detail are front-loaded. It earns its place and leaves no redundant 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 single-parameter validation tool with an output schema and read-only/idempotent annotations, the description covers the essential behavior. It is slightly short of a 5 only because it does not address the adjacent EAN/Luhn tools or potential overlap between ISBN-13 and EAN-13.
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?
The isbn parameter has a complete schema description ('ISBN-10 or ISBN-13; dashes/spaces allowed'), so schema coverage is 100%. The tool description does not add new parameter-level detail beyond restating ISBN-10/13; 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?
Description states a concrete verb (Validate), a specific resource (ISBN-10/ISBN-13), and the exact checksum algorithm for each. This distinguishes it from sibling checksum tools like luhn_check, ean13_check, and sedol_check without needing to inspect schemas.
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 clear ISBN framing implies when it should be used, and the enumerated mod-11 vs 1,3-weight mod-10 algorithms implicitly signal it is not a generic checksum validator. However, it never explicitly states when to choose this over ean13_check or luhn_check, nor gives exclusions or alternatives.
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.
Each tool targets a distinct identifier type or data source: every checksum validation is for a specific standard (IBAN, LEI, VAT, etc.), and the on-chain and rental tools are clearly separate domains. There is no ambiguity between tools; even similar-sounding checks like 'luhn_check' and 'ean13_check' are distinct algorithms with explicit descriptions.
Most validation tools follow a 'X_check' pattern (iban_check, swift_bic_check, ein_format_check), but others deviate: 'company_number_format' uses a noun_noun structure, 'block_info' is noun_noun, and 'batch_validate' and 'context_distill' use verbs. While the pattern is not uniform, the names are readable and the convention is understandable, just not fully consistent.
With 28 tools, this server exceeds the typical 3-15 well-scoped range and even the 16-25 heavy range. The server covers multiple unrelated domains (identifier validation, blockchain queries, rental fraud, text processing), which inflates the count. While each tool is individually justified, the overall surface feels overly broad for a single MCP server.
For each sub-domain, coverage is strong: identifier validation includes a wide range of international standards, on-chain queries cover balances, activity, and settlement history, and rental tools provide risk, verdict, and deposit guard. Minor gaps exist (e.g., no country-specific tax IDs beyond what's listed, no transaction history for arbitrary tokens), but the visible coverage is comprehensive for the stated purposes.