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

Annotations already declare the write profile (readOnlyHint=false, idempotentHint=false, destructiveHint=false). The description adds the meaningful behavioral constraint that titles are unique, which explains the non-idempotent hint and implies a failure path on collision. It stops short of stating the error behavior or required permissions, so not a 5.

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?

Front-loads the core action, then uniqueness/routing, then body and tag semantics, with no redundant sentences. Every sentence carries distinct information.

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?

Covers purpose, collision handling, body format, linking syntax, and tag intent for a three-parameter create tool with no output schema. The main gap is the return shape (e.g., created note id), but safety is already covered by annotations, so the definition is otherwise call-ready.

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 all three parameters are already documented, including markdown formatting and [[links]] in body. The description adds only the rationale that tags aid later retrieval, which is marginal beyond the schema. Baseline 3 is appropriate when the schema does the heavy lifting.

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?

States a specific verb and resource ('Save a new note'), and explicitly routes the update case to the sibling kb_update_note. An agent can distinguish this from kb_update_note, kb_get_note, and kb_list_notes without opening any schema.

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?

Gives an explicit alternative and the condition that selects it: 'Titles are unique; if one exists, use kb_update_note instead.' This is exactly the when-to-use / when-not-to-use routing that makes a description actionable.

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