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

Annotations only cover the safety profile (readOnlyHint=false, destructiveHint=false, openWorldHint=false). The description goes well beyond: it discloses that the tool fails with conflict once the decision is settled, may return a needs_confirmation envelope, and that repeatWeeklyUntil writes one row per week capped at 60, each movable.

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 purpose and the primary alternative, and each sentence carries a distinct decision-relevant fact. It is dense and slightly run-on, but nearly every clause earns its place.

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?

No output schema exists, and the description supplies the important return signals (conflict on settled decisions, needs_confirmation with a matching approvalId param). For a 13-parameter mutation tool this is close to complete, though a brief note on the success return shape would close the gap.

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 85%, so the schema already documents most parameters. The description nonetheless adds cross-parameter semantics the schema names only individually: all-day by default unless startTime accompanies timeZone, and the per-week row behavior of repeatWeeklyUntil.

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 plan item to an OPEN decision') and immediately clarifies what a plan item is ('the work that carries it out: a post, a launch step, an email'). It distinguishes itself from ledger_entries_create by explaining when the same date should be recorded as a decision instead.

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 explicit routing: use this for work, use ledger_entries_create if the date 'costs money or time and comes with an expectation'. It also names concrete conditions for omitting entryId, using repeatWeeklyUntil, and providing startTime/timeZone.

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