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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, covering safety and side effects. The description adds the BM25 algorithm and the knowledge base scope, which provides some behavioral context beyond the annotations (e.g., that it is a free-text search). However, it does not disclose details like result ordering, pagination limits, or error behavior, which are not covered by annotations. Given the annotations cover the critical safety profile, a 3 is appropriate.

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 a single, well-structured sentence with no redundancy. The primary action ('BM25 full-text search') is front-loaded, followed by scope and domain. Every word adds value, and there is no extra fluff or repeated information from the schema.

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 search tool with only two parameters, both fully documented in the schema, and annotations covering safety and idempotency, the description is complete. It specifies the search algorithm, the corpus (knowledge base sections), and the domain. No additional context (like return format) is necessary since this is a standard search operation and no output schema exists.

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%, with both parameters (query and topK) already documented in the schema. The description adds minor context by specifying the query language (Polish or English) is already in the schema, and the BM25 algorithm implies free-text input. This adds a little meaning (free-text vs exact match) but does not substantially compensate beyond the schema. Baseline 3 is correct.

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 (search), the resource (rafsoft.net knowledge base), and the scope (FAQ, docs, blog, pricing). It also specifies the domain (Faktura VAT Polish invoicing software). This distinguishes it from siblings like get_faq (targeted FAQ retrieval) and get_product_info (specific product details). An agent can immediately understand what this tool does and how it differs.

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 clear context: it is a full-text search over a knowledge base, implying use for open-ended queries rather than known-item lookups. However, it does not explicitly mention when not to use it or reference sibling tools (e.g., use get_faq for a specific FAQ entry). The context is clear but lacks explicit exclusions or alternatives.

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