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

Annotations already cover readOnly, idempotent, openWorld and non-destructive, so the safety profile is handled. The description goes further by disclosing the $0.010 cost, that payment instructions are returned for the Saylor endpoint, and that no provider account is required — non-obvious operational facts an agent must plan around. It omits rate limits, caching/expiry of resolved metadata, and error behavior for unresolvable DOIs, so it falls short of a 5.

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 compact sentences, front-loaded with purpose and outputs before scope and cost details; no filler. The cost and payment sentence is genuinely load-bearing rather than decorative. Slightly elliptical phrasing ('Saylor endpoint') is the only mild drag on readability.

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, the description must characterize the return, and it does — it lists the four categories of data returned and the two excluded categories. It also flags the unusual payment-instruction response path, which an agent would otherwise not anticipate. Missing is what happens on failure or for a nonexistent DOI, a real gap for a paid call.

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 parameter and schema description coverage is 100%, with the schema already stating the identifier format including the optional https://doi.org/ prefix. The description adds no further meaning about the parameter — no accepted DOI forms beyond the schema, no validation or normalization rules. The baseline of 3 applies when the schema fully carries the parameter burden.

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 uses a specific verb and resource ('Resolve a DOI') and enumerates the outputs delivered: normalized publication metadata, citation text, identifiers, and source links. The scope is also bounded by the explicit exclusion of abstracts and full paper text, which makes it distinguishable from siblings like get_papers_report. It stops short of naming an alternative tool by name, which keeps it out of the top band.

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 the resource ('resolve a DOI') but there is no explicit when-to-use or when-not guidance, and no sibling is named as an alternative. The exclusion clause ('Abstracts and full paper text are excluded') clarifies scope rather than routing. The mention of cost and payment is a prerequisite, not a selection rule.

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