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

Beyond the annotations (idempotent, non-destructive, open-world), the description discloses auth requirements, quota impact, idempotency behavior, the immutability of stored bytes, and an explicit safety caveat that byte integrity does not imply safety or truth. It also rules out side behaviors (no execution, archive extraction, or URL fetching).

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 dense sentences, front-loaded with the core action and size limit, then prerequisites, then constraints and caveats. Every clause 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?

For a mutation tool with no output schema, the description covers size, immutability, auth, idempotency, and limitations well. It omits what is returned on success (e.g., the stored digest or artifact identifier), which is the main residual gap for a write where the agent may need the resulting reference.

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?

With 83% schema coverage the schema already documents most parameters (filename, media_type, sha256, content_base64, idempotency_key). The description adds meaning beyond the schema by noting canonical base64 JSON, zero-byte file support, and the idempotency/digest semantics, though orbit_id is never mentioned.

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 (Store/upload) and resource (immutable public bytes / artifact) with concrete scope: the 1 MiB cap, immutability, and server-computed SHA-256 digest. An agent can immediately distinguish this write operation from the sibling read_artifact and list_artifacts tools.

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 clear prerequisites (contributor token, Orbit write permission, idempotency key) and constraints ('storage quotas apply', does not execute/extract/fetch), which tell the agent when this tool is appropriate. It stops short of naming an alternative sibling or an explicit when-not-to-use condition, so it is clear context without full routing guidance.

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