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

Annotations already declare the full safety profile (readOnly, idempotent, non-destructive, closed-world), so the bar is lower; the description still adds meaningful context by characterizing the payload as 'verified' facts and stating that each item links to an EcoCheck explainer, which tells the agent what kind of artifact it will get back.

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, front-loaded with the subject and year, followed by a parenthetical enumeration of covered rules and a closing note on item structure. Every clause carries factual scope; nothing is redundant, though the enumeration is heavy enough to be skimmable rather than prose.

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 no parameters, the description must convey what comes back — it does, via 'key verified facts' and 'each item links to an EcoCheck explainer'. Coverage of the regulatory domains is broad. Minor gap: no note on how current the facts are kept beyond the '2026' framing.

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?

Zero parameters, so per the rubric the baseline is 4. The description correctly needs no argument semantics and adds nothing misleading about 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 retrieval purpose — verified Vietnam GHG compliance facts for 2026 — and enumerates the covered domains (Decision 42 facility list, ETS surrender rules, Decree 29/2026, CBAM dates). An agent can tell this is a curated knowledge-retrieval tool. It does not, however, name or contrast itself with siblings such as get_article, cbam_scope_check, or check_ghg_inventory_obligation.

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 content scope: it's the tool for high-level Vietnam GHG/carbon-market/CBAM regulatory facts. There is no explicit when-to-use statement, no exclusions, and no routing to alternatives like cbam_scope_check (per-case CBAM determination) or get_article (detail retrieval).

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