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

Goes well beyond the annotations (readOnlyHint=false, openWorldHint=false, destructiveHint=false): it discloses the idempotency requirement, the exact return branches, explicit negative scope ('never returns upload_url, r2_key, provider credentials, or raw tenant identifiers'), the required Authorization header, and the server-side enforcement set (mcp.launch.prepare, tenant ownership, rate limits, concurrency, size, type, R2-prefix checks). This is exactly the operational context an agent needs beyond the safety hints.

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?

Front-loaded with the core purpose and the idempotency requirement, then negative scope, then the follow-up mechanics and the example. Dense but every sentence carries substantive information; the final enforcement list is long but load-bearing rather than 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 and only sparse annotations, the description compensates by documenting both return branches, the follow-up HTTP step, auth requirements, and enforcement behavior. An agent has everything needed to invoke it correctly and route the resulting bytes.

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 0%, so the description carries the full burden and does: file_size range (1..500MB), file_hash format (lowercase 64-hex), upload_attempt range (1..3, default 1), idempotency_key stability requirement, plus a concrete worked example. Only connection_context is left unexplained, a minor omission given the exhaustive coverage of the real inputs.

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+resource: prepare or reconcile a tenant-owned creative upload. It clearly scopes the operation as a pre-upload step versus a byte transfer. It does not explicitly differentiate from the v1 sibling 'creatives_request_upload' or route to 'creatives_confirm_upload', so it falls short of full sibling disambiguation.

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?

Usage is implied through the described lifecycle (call this first, then POST bytes to the returned endpoint), and it describes the two return branches (upload_endpoint when bytes are needed vs dedup_success for a ready object). However, it never names an alternative tool or states when-not to use this, so the agent must infer the flow position from the sibling list.

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