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

Annotations only declare the generic write profile (readOnlyHint=false, destructiveHint=false, openWorldHint=false). The description adds the non-obvious behavioral trait that this is a conditional write: it is a no-op returning 'ok false' when no daily/weekly pass is running, and its output is consumed by the next pass. It does not say whether repeated notes accumulate or are superseded, which would have pushed this to a 5.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-loaded with the core action, then preconditions, then alternative routing, and each sentence carries information. The parenthetical asides (tool names, 'ok false') make it slightly dense to parse, but nothing is 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?

For a 2-param write tool with no output schema, it covers purpose, when the write takes effect, the failure signal ('ok false'), and which sibling to use for adjacent intents. Remaining gap is the return payload beyond the ok flag and whether notes stack across passes.

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; both parameters are already documented in the schema. The description adds the implicit requirement 'It needs an act key', but that key is not a parameter in the schema, so it introduces context the agent must infer rather than clarifying the two declared parameters.

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: 'Adds a note to the planning pass that is running, for the next pass to read (journal_read).' It names the counterpart reader tool and the intended content of the note (what you're waiting for, what to check, what you decided against), so an agent can distinguish it from journal_read, owner_fact_set or learning_write 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?

Explicit preconditions and exclusions: 'Only a weekly or daily pass keeps one: from the chat or the owner's AI no pass is running, so nothing is kept (ok false).' It also routes alternative intents to named siblings ('a fact goes in owner_fact_set, something learned in learning_write'), which is exactly the when-to-use / when-not-to-use / alternative guidance the dimension asks for.

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