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

Annotations only declare readOnlyHint=false, so the description carries the real weight and delivers: default dry-run behavior with a described proposal payload, idempotency/replay semantics, the AUTH_REQUIRED failure mode, tier gating, and the guarantee that notes can never be published. This is a mutation tool whose side effects and failure modes are fully disclosed.

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 operation type and the dry-run default, then layered requirements and error behavior. Caps-for-emphasis keep it scannable, and every sentence (idempotency, auth, privacy, char cap) carries distinct operational information.

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, but the description compensates by sketching the return shapes ({dry_run: true, tool, args, idempotency_key, message} and {replay: true, ...}). With mutation semantics, auth, and tier requirements all covered, an agent has everything needed to invoke 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 the baseline is 3, but the description adds meaning beyond the schema: slug must already exist on /reading-list, the 500-char body cap, and that _idempotency_key can be reused to guarantee replay safety. It does not explain key auto-derivation beyond what the schema states, keeping it short of a 5.

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?

Opens with a specific verb+resource+scope: 'save or update YOUR private note on an Oxford Ledge reading-list entry,' and immediately distinguishes itself as one of TWO mutating tools, naming the other (ol_paper_trade). An agent can identify exactly what this does and how it differs from its write peer.

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 (saving/updating a private reading-list note), names the alternative mutating sibling, and lays out the exact execution protocol: dry-run by default, then re-call with _dry_run: false and the same _idempotency_key. Prerequisites (Plus tier, authenticated caller) and the local-stdio limitation are spelled out.

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