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

Annotations only carry readOnlyHint, so the description adds meaningful behavior: it renders, validates, and returns a manifest rather than submitting anything, and signing happens externally in the web console. It still says nothing about validation failure behavior or how missing/extra field values are handled.

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 front-loaded sentence covering render, validation, and the handoff to signing, with the template dependency folded in as a parenthetical. No wasted clauses.

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 four-parameter, fully-documented tool with no output schema, the description covers purpose, prerequisource, validation, and the next step for the returned artifact. Gaps are minor: no statement of failure modes or how template/values mismatches surface.

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% with enums documented for locale and network, so the schema carries the burden. The description only references 'given field values' and the template, adding no syntax or constraint details beyond what the schema already states.

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 and resource chain: renders a manifest template with given field values, validates it, and returns a signable manifest. That is clearly distinct from the fixed-purpose siblings (build_fungible_token_manifest, build_nft_collection_manifest), though the differentiation is implied by 'template' rather than stated outright.

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?

Gives real workflow context: pull template ids and fields from list_manifest_templates, then sign the result in the web console. It does not spell out when to prefer this over the other build_*_manifest tools or what happens when values fail validation, so it stops short of 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.