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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so safety is covered. The description adds genuine behavioral detail beyond that: timeline events are returned 'oldest first, with their sources, plus the official lifecycle dates', and glossary text matches the Guide's mouse-over verbatim.

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 organized as three parallel labeled clauses ('section timeline... section faq... section glossary...'), which mirrors the enum and scans quickly. It is dense but every clause carries distinct information about a different 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?

There is no output schema, so the description must characterize returns, and it does so for all three sections (events with sources plus lifecycle dates; questions and answers; definition text). What is missing is failure behavior, such as what happens when product_slug or term is omitted for a section that requires it.

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 documents term, query, section and product_slug, and the enum values are self-evident. The description restates which parameter each section needs but adds no syntax, format, or edge-case meaning beyond what the schema provides, so the baseline of 3 applies.

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 opens by naming the resource ('Three parts of the Guide') and enumerates exactly what each of the three modes returns, so an agent can tell timeline, faq, and glossary apart at a glance. It falls short of a 5 only because it never distinguishes itself from the sibling get_guide_summary, which an agent must infer.

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?

It gives mode-specific invocation context: 'term' is 'Needed for glossary', 'product_slug' is 'Needed for timeline and faq', and the query is described as an optional narrower for faq. That is clear conditional guidance for each branch, though there is no explicit statement of when to prefer this tool over get_guide_summary.

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