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

Annotation Contradiction: readOnlyHint=true conflicts with the description's statement that 'Set mark_read:true to flag returned events read so the next call only shows newer ones' — this implies persistent state mutation. While the description otherwise discloses payload contents and feed behavior, the contradiction with the read-only annotation forces a score of 1.

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 concise, front-loaded sentences cover purpose, return payload, filtering, side effects, and polling suitability. Every sentence earns its place with no redundancy or filler.

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?

Despite no output schema, the description explains what each event carries (source, citation_uri, raw payload) and how the tool behaves (filtering, mark_read side effect, polling). Parameters limit and unread_only are adequately covered by the schema, so the description is complete for this tool's complexity.

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%, providing a baseline of 3. The description adds value by giving a concrete type example ('sec_8k') and clarifying the consequence of mark_read (next call shows only newer events), going beyond the schema's short 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 description opens with 'Pull fired events from your subscription feed', a specific verb and resource. It distinguishes this tool from siblings like list_subscriptions and recent_changes by focusing on fired alert events with payload details.

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?

Provides clear context: filtering by type and/or since, polling suitability ('Polls work fine'), and an alternative access method via a direct URL. It stops short of explicitly naming sibling alternatives or stating when not to use this tool, so it misses the top score.

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