count_messages

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

With no annotations, the description carries the transparency burden. It discloses that the tool scans stable 200-message pages and does not return bodies, which is useful. However, it omits important behavioral details such as the max_messages cap and potential truncation of counts, limiting full transparency.

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?

The description is a single, front-loaded sentence with no filler words, earning every character. However, the term 'stable' is jargon and could confuse agents, slightly reducing clarity.

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 tool with five optional parameters and an output schema, the description is far too brief. It fails to explain parameter meanings, the max_messages limit, and when to use this tool versus siblings, leaving significant gaps in context for correct invocation.

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?

The schema description coverage is 0%, and the description does not explain any of the five parameters (chat, period, talker, timezone, max_messages). 'Bounded period' only vaguely references the period parameter, leaving all other parameters semantically unexplained.

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 clearly states the tool 'Count a bounded period without returning bodies', using a specific verb and resource, and distinguishes it from reading tools. It clarifies the scope (bounded period) and the key behavior (no bodies), which differentiates it from siblings like read_chat_range.

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?

The description implies the tool is used when only a message count is needed, but it does not explicitly state when to use it over alternatives or mention any exclusions. There is no naming of sibling tools or comparison to similar functions, leaving usage context vague.

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