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

Annotations only supply destructiveHint=true; the description usefully discloses the trait that explains it — the resulting URL is public, shareable and time-limited, meaning the artifact is exposed beyond the authenticated account. It does not mention auth requirements, rate limits, or whether previously issued URLs are revoked, so it stops short of full transparency.

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?

Two tight sentences, front-loaded with the action and scope, followed by the REST endpoint mapping. Every clause earns its place; 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 two-parameter mutation tool there is no output schema, so the description arguably should say what comes back (the URL and its expiry), and it omits the sibling-alternative routing that matters most here. Adequate but with clear gaps.

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% — both secureFilename and expiresAt (UNIX seconds) are fully documented in the schema. The description restates 'by its secure filename' and the time-limited nature but adds no syntax, format, or constraint information beyond what the schema already 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?

States a specific verb (Create) and resource (public download URL for a build artifact), and the qualifier 'public (shareable, time-limited)' implicitly contrasts with the authenticated sibling codemagic_get_artifact_download_url. An agent can tell what it produces without opening the 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?

Usage is implied by 'public (shareable, time-limited)' — you use this when you need an external, expiring link — but the description never names the obvious alternative codemagic_get_artifact_download_url or states when-not to use this one. No explicit when/when-not guidance.

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