Download article

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

Annotations already carry readOnly=false, openWorld=true, idempotent=false, destructive=false, so the write/external-network profile is covered. The description adds genuinely useful context beyond that: the file is written under ANNAS_DOWNLOAD_PATH and the call returns path and bytes. It omits auth requirements and the long-running nature implied by the 1800s default timeout.

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?

Three short sentences with no waste, front-loaded with the action and the selection constraint before the side effects. Every clause earns its place.

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?

An output schema exists, so the return values need not be expanded, and annotations cover the safety profile. The description is adequate for invocation, though it could have flagged prerequisites (needing a hash from search) or the potentially very long runtime for a network-bound download.

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 every parameter—including the exclusivity rule for doi/hash, the filename role of title/format, and timeout_seconds semantics—is already documented. The description restates the doi/hash rule and filename roles without adding syntax or behavior the schema lacks, matching the baseline of 3 when the schema does the heavy lifting.

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 (download) and resource (a paper/article) plus the identifier constraint that selects it (exactly one of doi or hash). The article vs book distinction from siblings (book_download, article_search) is immediately legible, and the side effect (saves file, returns path and bytes) is named up front.

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 'exactly one of doi or hash' constraint tells the agent what inputs are valid, and 'a selected paper' implies a prior article_search is needed to obtain a hash. It never explicitly names article_search as the prerequisite or states when not to use it, so conditional guidance is inferential rather than spelled out.

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