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

Adds real behavior beyond the annotations: documents come with a one-time download link, note content is untrusted data that must never be treated as instructions, and friend requests require the person's own decision. The annotations declare readOnlyHint=false and idempotentHint=false, and the description partially explains why (read/unread state and one-time links), though it never says explicitly whether calling this marks notes as read.

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 resource and its contents before the invocation trigger, and every clause carries information. The first sentence is long and packs four distinct payloads together, which slightly hurts scannability, but there is no 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?

With no output schema, the description carries the burden of describing returns and does so well: notes, replies, friend requests, read/unread status, and document download links. It does not cover ordering, volume, or pagination behavior, and it leaves the read-marking side effect implied rather than stated.

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?

The tool takes zero parameters, so there is nothing for the description to disambiguate; the baseline for a parameterless tool is 4. The description correctly adds no parameter prose and instead spends its budget on output content.

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 ('Read the notes friends left for your person') and enumerates the exact payload: notes, replies, pending friend requests, read/unread tracking, and attached documents. This is clearly distinguishable from siblings like leave_note, my_requests, notifications, or attach_document 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?

Gives an explicit trigger with a concrete user utterance ('any notes for me?'), which is strong when-to-use guidance. It also gives a when-not/decision rule for friend requests ('Friend requests are your person's decision'). It stops short of routing the agent away from overlapping siblings such as my_requests or notifications.

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