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

With no annotations provided, the description carries the full burden and does reasonably well: it discloses the session scope ('visible to the logged-in session'), the returned fields, and the matching semantics of the filter. It does not mention authentication prerequisites, pagination, or result limits, which are minor gaps for a read-only listing tool.

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?

Two dense sentences, front-loaded with the resource and scope, followed by the usage purpose and the optional filter. No filler or redundancy.

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?

Although there is no output schema, the description supplies the return field set, the session scoping, and the routing purpose, which is everything an agent needs to call and consume this single-optional-parameter listing tool.

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 parameter is already fully documented. The description's note that `filter` does a case-insensitive substring match on name/username/id largely restates the schema, adding no new syntax or format detail. Baseline 3 is appropriate.

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 (List) and resource (Telegram dialogs/chats/channels/groups/users) scoped to the logged-in session, and even previews the return shape [{id, type, name, username}]. It is clearly distinguishable from siblings like tg_messages and tg_download, which it names as downstream consumers.

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 states when to use it ('Use it to find the chat id or @username to pass as `chat` to tg_messages / tg_download'), which routes the agent correctly. There is no explicit when-not or negative case, but the usage context is unambiguous.

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

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

With no annotations, the description carries the full burden. It usefully discloses the skip-existing behavior ('Already-present files are skipped'), the default of 100, and that since_id overrides last_n. It omits operational context such as Telegram auth/login requirements, rate limits, and whether the destination directory is created automatically.

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 action and return value before the parameter notes, and every clause is functional. It is slightly dense with parenthetical parameter guidance, but there is no 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?

With no output schema, the description correctly states the return ('absolute paths of newly downloaded files'), and it covers the key filters and skip behavior. The main gap for a network-dependent tool is the absence of any authentication or failure-mode context.

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. The description goes beyond the schema by translating parameters into intent phrases ('everything new after message X', 'the latest N media messages'), which helps an agent map a natural request onto the right parameter rather than merely matching names.

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 ('Download media files from one chat'), names accepted chat identifiers, and specifies what is returned (absolute paths of newly downloaded files). It is clear and testable, but does not explicitly differentiate itself from the sibling tg_download_url, which an agent could confuse it with.

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?

Usage is implied rather than stated: extensions for filtering by file type, since_id for incremental fetching, last_n for the latest N. There is no explicit 'use this when / use tg_download_url instead when' guidance against the sibling tools.

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

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

With no annotations, the description carries the full behavioral burden. It does disclose two useful traits — it returns absolute paths of newly downloaded files and skips already-present files (--skip-same) — which is real idempotency information. But it says nothing about authentication/prerequisites for Telegram access, partial-failure behavior, or whether downloads are network-bound, leaving meaningful gaps.

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?

Three short sentences, no filler; the core action and return value come first and the routing hint and skip behavior follow in priority order. Every sentence earns its place.

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?

With a fully described schema and no output schema, the definition covers the essentials: what it downloads, from what input, and what it returns. It falls short only on prerequisites (auth/session) and failure behavior for what is a file-writing, network-dependent operation.

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%, so dest, urls, and extensions are already fully documented in the schema, including the https://t.me/ prefix requirement. The description adds no extra semantics about these parameters, so the baseline 3 applies.

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 ('Download the media of specific Telegram messages given their t.me links') and pins the input form with a concrete example URL. The clause 'rather than a chat to scan' implicitly separates it from the chat-scanning sibling tg_download, so an agent can route without opening schemas.

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?

Gives an explicit selection condition: 'Use when you already have message links rather than a chat to scan.' That clearly signals when this tool applies and implies the alternative (bulk chat scanning) is a different tool, though it never names tg_download explicitly.

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

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

With no annotations, the description must carry the full behavioral burden. It discloses the 'Read-only' safety profile and that export is done via tdl, but says nothing about auth requirements, rate limits, or error behavior. It adds useful context beyond structured fields but leaves real gaps.

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?

A single front-loaded sentence that covers purpose, parameters, and return shape without fluff. It is dense with parenthetical asides but every clause earns its place.

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 4-param read tool with no output schema, the description usefully describes the returned object shape and the backend. It omits auth/pagination/failure detail, but the core information an agent needs to invoke it is present.

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%, so each parameter is already documented, including the since_id-overrides-last_n relationship. The description reinforces intended usage of last_n and since_id but adds no syntax or format detail beyond the schema, so baseline 3 is appropriate.

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 (export) and resource (recent media messages from one chat) and even specifies the return shape {id, date, file, text}. This clearly distinguishes it from siblings tg_chats (listing chats) and tg_download (fetching files).

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 explains when to use last_n ('the last N media messages') versus since_id (incremental reads after a known id). It does not name sibling alternatives like tg_download for a specific message, but the parameter-selection guidance is clear.

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

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

Without annotations, the description carries full burden. It discloses that the tool never errors and returns {logged_in:false, hint} when missing, covering error handling and output format. However, it omits details about side effects or performance, but these are minimal for a status check.

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?

Two sentences with no wasted words. The first sentence states purpose, the second adds usage guidance and behavior. Front-loaded and efficient.

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?

Given no parameters, no output schema, and low complexity, the description covers purpose, usage, and behavior. It lacks explanation of what 'hint' contains or what 'usable' means, but these are minor gaps.

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?

No parameters exist, so schema coverage is 100% and the description need not add parameter info. Baseline 4 is appropriate as the description adds no parameter details but doesn't need to.

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 uses a specific verb ('Check') and resource ('local tdl Telegram session'), clearly stating its function to verify login status. It distinguishes itself from siblings by being a diagnostic tool to call before other tg_* tools, though not explicitly mentioning what it doesn't do.

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 advises calling this tool first if another tg_* tool fails or before starting Telegram work, providing clear context for when to use it. No alternatives are needed given its singular purpose.

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