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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint, so the safety profile needs no restating. Beyond that the description adds real behavioral context: results are ordered newest first, only substantive amendments are included (an implicit filter), the source is the official eCFR, and one mode walks a section paragraph by paragraph. It does not say how many amendments are returned or what happens when none exist.

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?

A single dense sentence that front-loads the primary operation and appends the optional comparison mode last. There is no filler, and each clause carries distinct information (scope, filter, ordering, source, alternate mode).

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 five parameters, two distinct modes and no output schema, the description leaves the return shape unexplained: an agent cannot tell whether amendments come back as citations with dates, summaries, or diffs, nor how large a result set to expect. The annotations cover the safety profile, and the mode logic is covered, but the missing output characterization is a real gap for a five-parameter tool.

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 the schema already defines every parameter including the conditional relationship between section, since and compareTo. The description reinforces that section is the optional narrower scope and that compareTo is a section-only mode, but it adds no format or constraint detail the schema lacks. Baseline 3 is appropriate.

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?

"List the substantive amendments to a CFR part (or section) since a date, newest first, from the official eCFR" gives a concrete verb (list), a precise resource (CFR part/section amendments), and scope qualifiers (substantive, since a date, newest first). It also separates the tool's two modes (amendment listing vs. section comparison). It does not reference any sibling such as cfr_lookup or cfr_search, so an agent gets no explicit differentiation against those.

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 phrasing ("since a date", "optionally compare one section between two dates"), which conveys that comparison is a secondary, section-only path. There is no explicit statement of when to prefer this over cfr_lookup/cfr_search, nor any when-not or prerequisite guidance.

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