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

Annotations only supply readOnlyHint=false, so the description carries the burden and delivers: dry-run-by-default semantics, exact proposal/replay return shapes, idempotency behavior, Researcher tier plus authenticated-caller requirement with AUTH_REQUIRED on local stdio, privacy guarantee, and API-key dependency. This is unusually rich disclosure for a write tool.

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 critical fact ('WRITE (opt-in)') and every sentence carries operational information, but the paragraph is dense and the dry-run/idempotency mechanics are packed into long clauses. Slightly more than strictly needed, though nothing is truly wasted.

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 write tool with no output schema, the description supplies the return shapes (proposal and replay objects), auth and tier prerequisites, failure mode (AUTH_REQUIRED), privacy constraints, and the full execute flow. An agent has everything required to call it 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 coverage is 100%, so baseline is 3; the description adds genuinely new meaning by requiring that `slug` already exist on /reading-list, and reinforces the 500-char `body` cap and its privacy. It does not, however, clarify how an auto-derived `_idempotency_key` is produced beyond 'auto-derived if omitted'.

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 or update YOUR private note on an Oxford Ledge reading-list entry') and immediately scopes it against siblings by naming the only other mutating tool (ol_paper_trade). An agent can identify the operation without opening the 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 explicit when-to-use context (save/update a private note) and when-not (notes can never be published here; publishing requires the dashboard flow). It also spells out the operational sequence: call once to get a dry-run proposal, then re-call with _dry_run: false plus the same idempotency key to execute.

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