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

Annotations already declare readOnly, idempotent, non-destructive, and closed-world, so the safety profile is covered. The description adds genuine context beyond that: it reveals the tool returns an inventory of content-addressed shards and that binary payloads are NOT included and must be retrieved via REST — a real behavioral constraint that shapes how an agent chains calls.

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 core resource front-loaded and the important caveat trailing after a semicolon. Every clause carries information; nothing is redundant.

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 one-parameter, non-destructive read with no output schema, the description covers what is produced (shard inventory) and the key limitation (no binaries). It falls short on the one thing left undocumented: what flow_id is and where to obtain it, which is essential to actually invoking the 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?

There is a single required parameter, flow_id, with 0% schema description coverage and no explanation in the description. An agent can only infer that flow_id scopes the inventory to a BIS flow; format, expected values, and how it relates to the sibling tools' identifiers are undocumented.

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?

States a specific verb ('Discover') and a specific resource ('content-addressed BIS shard inventory'), which distinguishes it from the data-returning siblings bis_observations and bis_records. It does not name a sibling or explicitly contrast itself, and the jargon ('content-addressed shard inventory') assumes domain knowledge.

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 clause 'binary shards remain REST downloads' implies a when-not: do not use this tool to fetch shard binaries, follow up over REST. However, there is no explicit guidance on when to choose this manifest over bis_observations, bis_records, or corpus_catalog, so selection between siblings is left to inference.

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