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

Annotations already declare readOnlyHint, destructiveHint=false, and openWorldHint, so the safety profile is covered. The description adds the 'across all your messages' scope but says nothing about result format, ordering, or the hard cap beyond what the annotations/schema provide, so it is adequate rather than rich.

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?

A single tight sentence, front-loaded with the verb and resource, with no wasted words. The examples earn their place by illustrating query types.

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 read-only search tool with full schema coverage and annotations covering the safety profile, the description gives an agent enough to invoke it correctly. It could mention result ordering or that results are per-message, but nothing critical is missing.

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 description coverage is 100%, so every parameter is already documented. The description loosely signals the chatID and sender dimensions ('limited to certain chats or to messages from other people'), which reinforces but does not meaningfully extend the schema, making the baseline of 3 appropriate.

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?

Specific verb (search) plus resource (all your Beeper messages) and concrete query examples ('an address someone sent, a confirmation number') make the purpose immediately clear. It doesn't explicitly contrast with siblings like beeper_read_chats, so it stops short of a 5.

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 phrase 'optionally limited to certain chats or to messages from other people' hints at scoping usage, but there is no explicit when-to-use versus alternatives (e.g. beeper_read_chats for reading full threads) and no when-not guidance.

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