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 value beyond that by describing the result shape and rationale — matches are returned with 'why each matched: shared words, same page, same element, same source file' — which tells the agent how to interpret and justify the results. It stops short of covering cost, latency, or ordering of matches.

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?

Four sentences, each doing distinct work: the question, the two call modes, the return semantics, and the follow-up tool. The primary use case (pre-create duplicate check) is front-loaded in the first clause, and nothing is repeated from the schema or annotations.

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, yet the description still explains what comes back and why, and annotations carry the safety profile for a read-only, idempotent lookup. For a 7-param optional-arg search tool with full schema coverage, an agent has everything needed to call it and act on the result.

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 100%, so the baseline is 3, but the description adds real intent beyond the schema: text is 'what you are about to report', page is optional context, and itemId is the mutually exclusive mode for locating duplicates of an existing thread. The limit, includeResolved, selector and projectId parameters are left entirely to the schema, which caps this below 5.

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 with the question the tool answers ('Has this already been reported?') and then states a concrete verb+resource: find likely matches for a report text or an existing item. It explicitly separates itself from create_item (call before) and merge_items (call after), so an agent can route without opening any 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?

It gives an explicit when: before create_item, and with the text you are about to report, optionally with the page. It also names the alternative mode (pass an itemId to see what a thread duplicates) and the downstream action (merge_items folds one into the other), so the full decision path is spelled out with no inference required.

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