journal_write

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

With no annotations, the description carries the full burden and does well: it discloses file auto-creation, that same-day appends return the same file_id, the storage layer for notes (Layer 1 agent_note events), and the return shapes for each mode. It omits auth/permission requirements and error behavior.

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-loaded purpose followed by kind-by-kind breakdown, with return values parenthesized inline so the agent can scan quickly. It is dense and fairly long, but nearly every clause carries useful information rather than filler.

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?

There is no output schema, so the description correctly supplies return shapes per mode, and with no annotations it also covers storage semantics and file behavior. This is sufficient for an agent to invoke the tool correctly.

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%, so the baseline is 3; the schema already documents each field's per-kind requirement. The description restates the kind-to-required-field map and adds what each kind semantically means, but adds little about parameter syntax or formats beyond the schema.

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 concrete verb and resource ('Write one event to the current project's journal') and then enumerates the three distinct modes with what each one does and stores. This clearly separates it from sibling journal tools like journal_distill, journal_status, and journal_housekeep.

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 mode-specific selection guidance, notably the explicit 'use when the user redirects what you're working on' condition for kind='intent'. It does not, however, state when not to use this tool or name alternative siblings for capturing information.

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