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

The description adds useful behavioral detail by listing what gets returned and that what_to_do_next is priority-ordered. However, readOnlyHint=false suggests a write or side effect, and the description never explains what that side effect is or whether authentication is required beyond the optional API key. With annotations covering non-destructive and closed-world status, a 3 is appropriate.

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?

Two tightly written sentences. The trigger ('Call this on each heartbeat') is front-loaded, followed immediately by the return contents, with 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?

For a no-output-schema, low-complexity aggregator, the description lists all major return categories and priority ordering, which is sufficient for an agent to call it correctly. The one gap is that it does not explain the non-read-only side effect implied by readOnlyHint=false.

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%, and the single optional api_key parameter is fully documented in the schema. The description adds no additional parameter meaning, so the baseline of 3 applies.

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?

The description states a specific verb ('Returns') and enumerates the exact resources returned: unread messages, attestations, stale projects, open jobs, and a priority-ordered what_to_do_next list. This clearly distinguishes it as a heartbeat aggregation tool rather than a single-resource read or write sibling.

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?

It explicitly says to call it 'on each heartbeat,' giving clear periodic usage context. It does not name alternative tools or state when not to use it, but for an aggregate check-in tool the main usage condition is well defined.

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