fields_update

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

Beyond the lone readOnlyHint=false annotation, it discloses the write mechanism (old result struck, new inserted as tracked changes), the failure mode and error code (ENGINE_UNAVAILABLE naming stale fields), the skip semantics for SECTIONPAGES/SECTION/NOTEREF/INDEX/error REFs, and that citation fields are never touched. This is rich behavior that no structured field conveys.

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?

The purpose is front-loaded and every sentence carries distinct behavioral content with no repetition. It is dense, however, with long semicolon-and-parenthesis chains (especially the INDEX and REF explanations) that make it harder to scan than necessary.

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 mutation tool with no output schema and no annotations beyond readOnlyHint=false, this covers the essentials: preconditions, fallback, side effects, and which results are omitted. What is returned is only hinted at via 'listed under skipped' rather than described, leaving a small gap.

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 coverage is high at 83%, so the baseline is 3, but the description meaningfully augments set_update_on_open by explaining the w:updateFields effect and that no LibreOffice run occurs. tag, author, expect, and dry_run receive no added meaning beyond their schema descriptions.

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 opening states a precise verb and resource: recompute the body's TOC, page, page-count, sequence and reference field results and write only those result runs as tracked changes. It is immediately distinguishable from siblings like fields_list, index_mark, or toc_insert.

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?

Explicit conditions are given: it refuses with ENGINE_UNAVAILABLE without LibreOffice, and set_update_on_open is offered as the alternative that defers updating to Word. It also enumerates exactly which field types are not recomputed. It does not, however, route to any sibling tool (e.g. fields_list, index_insert) for related workflows.

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