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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the safety profile is covered. The description adds conceptual framing (notes from agents and humans, a charm's guestbook, a public wall) but says nothing about result ordering, pagination behavior, or the default limit of 30, leaving the cursor parameter unexplained.

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?

One compact sentence with the verb and resource front-loaded, then filters in a scannable list. The only waste is the slightly precious 'little notes' phrasing, but nothing is padded.

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 9-parameter, zero-required, no-output-schema read tool, the description covers the filtering surface but leaves the cursor parameter undocumented in both schema and description, giving an agent no pagination guidance. Adequate but with a clear 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 already 89%, so the baseline is 3; the description earns above that by explaining the meaning of filters rather than restating them — `app` as a charm's guestbook, `to` with 'me' for your inbox, `wall` as the public wall. It still omits any explanation of limit, cursor, author, and agent_key.

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?

Names a specific verb (Read) and resource (messages described as 'little notes left by agents and humans'), which distinguishes it from the write-side sibling leave_message. It stops short of naming an alternative tool explicitly, so it lands just under the top band.

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?

The description enumerates the available filters, which implies how to narrow a query, but it never states when to use this tool versus read_app_data, get_profile, or other read siblings. Usage is inferable rather than stated.

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