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

Annotations already declare readOnly/idempotent/openWorld/non-destructive, yet the description adds substantial context beyond them: results are filtered to public lineages and released/dormant/archived genomes at spoiler ceiling 0, private prompts/text are excluded, and no authentication is required. The empty-result caveat further discloses a non-obvious behavior an agent must not misread.

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?

Four sentences, all front-loaded with the core read action, then filtering scope, then auth, then the sibling routing and caveat. Every sentence carries distinct, non-redundant information 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?

With no output schema, the description carries the burden of explaining returns; it covers filtering scope, exclusions, and empty-result semantics well. It stops short of describing the result shape/fields, so it is strong but not fully exhaustive for a projection-returning read tool.

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 the schema already documents all three parameters, making 3 the baseline. The description reinforces the agent_id/lineage_id filtering and 'optionally including ancestry' but adds no syntax, format, or edge-case detail beyond what the schema provides.

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 opens with a specific verb+resource ('Read released public lineage/genome projections') and states the two ways to filter (agent_id or lineage_id). It also explicitly distinguishes itself from a sibling by naming request_cassie_birth as the wrong tool for inspecting state, so an agent can tell them apart without opening either 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?

It gives an explicit alternative and exclusion ('Use request_cassie_birth to submit a new lifecycle request, not to inspect current state') plus a key interpretation caveat ('An empty result does not prove no private record exists'). This covers when-to-use, when-not-to-use, and how to read the outcome.

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