FastMCP Documentation Search Server

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

No annotations are provided, so the description carries the full burden. It states the action ('hash a string') but lacks behavioral details: it doesn't specify if the operation is deterministic, reversible, or idempotent; mention performance or rate limits; describe error handling (e.g., for empty strings); or explain the output format. For a tool with no annotations, this is a significant gap in transparency.

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—a single sentence with no wasted words. It's front-loaded with the core action ('hash a string') and includes essential detail (SHA-256). Every part earns its place, making it efficient and easy to parse.

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?

Given the tool's low complexity (one parameter, no nested objects) and the presence of an output schema (which handles return values), the description is somewhat complete. However, with no annotations and minimal parameter guidance, it lacks context on behavior, usage, and constraints. It's adequate for basic understanding but has clear gaps in guiding effective use.

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 description adds minimal meaning beyond the input schema. It implies the 'text' parameter is the string to be hashed, but with 0% schema description coverage, the schema only defines 'text' as a string without context. The description doesn't elaborate on constraints (e.g., length limits, encoding) or provide examples. Since there's only one parameter, the baseline is 4, but the lack of added semantic detail reduces it to 3.

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 verb ('hash') and resource ('a string'), specifying the algorithm (SHA-256). It distinguishes from siblings like 'add', 'scrape_page', and 'search_docs' by focusing on cryptographic hashing rather than arithmetic, web scraping, or document search. However, it doesn't explicitly differentiate from potential sibling hashing tools (e.g., 'hash_text_md5'), so it's not a perfect 5.

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 provides no guidance on when to use this tool versus alternatives. It doesn't mention use cases (e.g., data integrity checks, password hashing), prerequisites, or comparisons to other tools. With siblings like 'add' and 'search_docs', there's no explicit context for choosing 'hash_text' over them, leaving usage unclear.

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