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

Annotations declare readOnlyHint=true, but the description says 'Set mark_read:true to flag returned events read so the next call only shows newer ones' — a persistent state mutation. This directly contradicts the read-only annotation, making the safety profile inconsistent. The description also lacks discussion of auth requirements or feed persistence behaviors.

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, front-loaded with the core action and return payload. The only slightly extra detail is the registry URL, but it is justified for script/dashboard users; no filler or repetition.

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?

The description explains what is returned, how to filter, the mark_read side effect, and polling suitability. It omits unread_only semantics but the schema covers it; without an output schema, the payload description is adequate. The contradiction with annotations is the main 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 covers 100% of parameters with descriptions, so baseline is 3. The description adds concrete semantics: example type 'sec_8k', ISO timestamp for since, and the mark_read side effect. This extra guidance pushes it above baseline.

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?

Description opens with 'Pull fired events from your subscription feed' — a specific verb+resource that clearly distinguishes from sibling tools like recent_changes and list_subscriptions. It also specifies the return payload (source, citation_uri, raw event) and filtering options, leaving no ambiguity about what the tool does.

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 contextual guidance: filtering by type/since, polling suitability, and an alternative URL for scripts/dashboards. However, it does not explicitly differentiate when to use this tool over sibling tools such as recent_changes or list_subscriptions, nor does it state when not to use it.

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