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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so the safety profile is clear. The description adds scoping to the caller's own journal and lists the return fields, but does not mention pagination, ordering, or behavior on empty results. With annotations covering the safety profile, this is adequate but not rich.

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 front-loaded sentence with no filler. The parenthetical field list earns its place because there is no output schema to document the return shape elsewhere.

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 zero-required-parameter, read-only list operation, the description provides the essential return fields and scoping. It lacks explicit pagination or ordering caveats, but these are minor for a simple slot listing, especially since the only parameter is thoroughly documented in the schema.

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%, including a detailed deprecation note for vigil_key. The description itself does not need to add parameter semantics; the schema already carries that burden, so the baseline 3 applies.

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 uses a specific verb ('List'), identifies the resource ('your journal slots'), and names the returned fields (slug, size, last-updated). It is readily distinguishable from sibling operations like vigil_journal_get, vigil_journal_put, and vigil_journal_delete because it is explicitly a plural listing operation.

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 implies usage by saying 'List' but gives no explicit when-to-use guidance or alternatives. An agent must infer that individual journal slot operations belong to vigil_journal_get/put/delete; the description does not state exclusions or conditions.

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