list_announcements

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

Annotations already declare readOnlyHint=true and openWorldHint=false, so safety is covered. The description adds real behavioral context beyond that: reading does not clear the buffer, the empty-state string is 'Nothing announced yet.', and results are ordered oldest-first with politeness prefixes. It does not discuss growth/limits of the buffer, so not a 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?

Front-loaded with the core purpose, then supporting detail on format, clearing behavior, and the alternative. Dense but each clause earns its place; the inline quoted examples slightly lengthen it without waste.

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?

No output schema exists, so the description must describe the return value, and it does: one line per announcement with politeness prefix, plus the empty-state message. For a single-parameter read tool this is complete.

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% and the single 'session' parameter is documented in the schema ('Its name, from start_session'), so the schema carries the burden. The description adds nothing further about the parameter, making the baseline 3 correct.

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 ('List what programs in the session have announced to a screen reader') plus scope ('since it started, oldest first') and output format. An agent can tell this apart from siblings like get_program_output or wait_for without opening the 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?

Explicitly says when to use it ('to check what a screen reader user heard after an action') and names the alternative for the adjacent need ('to wait for one, use wait_for announcement'). Nothing 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.