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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=false, so the safety profile is covered. The description adds a genuinely useful behavioral note beyond those fields: it 'works on long documents in full', signalling no truncation or chunking limit. It says nothing about latency or output variability, hence 4 rather than 5.

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?

Two sentences with zero waste: the trigger and supported modes come first, followed by a one-clause exclusion routing the agent elsewhere. Every sentence earns its place.

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 two-parameter read-only tool with a full output schema and complete annotation coverage, nothing an agent needs to select or invoke it correctly is missing: purpose, modes, scope limit (long docs), and the competing tool are all stated.

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 both parameters are already documented, including the exact 'tldr'/'key_points'/'action_items'/'detailed' style values. The description roughly mirrors those modes in prose but adds no syntax or format detail beyond the schema; baseline 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?

States a specific verb and resource ('summarize one of their Xenition documents, notes or research') and enumerates the modes (TL;DR, key points, action items, fuller summary). It also explicitly names the sibling it is not, edit_artifact, so an agent can distinguish it without opening either schema.

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 an explicit trigger ('Use this when the user wants a summary...') and an explicit exclusion with a named alternative ('Do not use to change the document (use edit_artifact)'). Nothing about when/when-not is left to inference.

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