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

Annotations already declare readOnlyHint=true, so safety is covered. The description adds the workflow linkage (post-recover/replay tracking) but says nothing about pagination behavior, defaults, or result shape beyond what the schema already states.

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?

Three tight sentences: purpose with examples, usage context, and the REST mapping. Front-loaded and every clause carries 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?

For a read-only, zero-parameter-required list tool with full schema coverage, the description plus schema covers what an agent needs. Return/pagination semantics are partially handled by the iterator and limit schema fields, so the omission of an explicit result description is minor.

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 all four parameters (task, limit, status, iterator) are fully documented in the schema. The description adds no format or filtering nuance beyond it, making the baseline 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?

Names a specific verb and resource ('List Svix background tasks') and enumerates the task kinds (bulk replays, expunges, imports), plus the underlying REST endpoint. No sibling lists background tasks, so the scope is unambiguous.

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?

'Use it to follow up a recover or replay' ties the tool to a concrete workflow and implicitly routes from svix_recover_endpoint. It gives clear positive context but no explicit when-not or alternative-tool guidance.

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