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

Annotations already establish readOnlyHint=true and openWorldHint=false, so the safety profile is covered. The description adds genuinely non-obvious behavior: match ordering (titles before full text), German morphological matching with a concrete example („Kunden“ finds „Kunde“), and the exact shape of the result including a snippet with the match in bold — none of which is recoverable from the annotations or schema.

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?

Three short sentences, front-loaded with the core action, then matching semantics, then return shape. Every sentence carries information the agent cannot get from structured fields, and the German example is compact rather than verbose.

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 two-parameter, read-only search tool with no output schema, the description is nearly self-sufficient: it covers matching behavior and enumerates the returned fields including the highlighted snippet. The only minor gap is that result ordering across multiple matches and whether snippets are truncated are not stated.

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 coverage is 100%, so the baseline is 3, but the description earns more by explaining how the query string is interpreted — word-form tolerance and title-first matching priority — which the schema only calls "Words to search for." The limit parameter is left to its schema description, which already states the default of 10 and max of 50.

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?

"Search the vault" gives a specific verb and resource, and the following sentences specify what is matched (titles first, then full text), so an agent knows exactly what this tool returns. It stops short of naming a sibling such as list_notes to contrast "search" against "browse", so differentiation is inferable rather than explicit.

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?

Usage is implied: the tool searches rather than reads or lists, and the agent can infer it should use search_notes to locate notes by keyword. However, there is no explicit when-to-use statement and no routing guidance toward list_notes, read_note, or get_backlinks when the goal is enumeration or traversal instead of keyword lookup.

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